python学习之函数

1 func = lambda a: a+1
2 print(func(10))

1 //0， None， 空列表， 空字符串， 空元祖， 空字典
2 //返回的值都是False

  1 abs(x)
  2 
  3     Return the absolute value of a number. The argument may be an integer or a floating point number. If the argument is a complex number, its magnitude is returned.
  4 
  5 all(iterable)
  6 //所有x为真才为真
  7     Return True if all elements of the iterable are true (or if the iterable is empty). Equivalent to:
  8 
  9     def all(iterable):
 10         for element in iterable:
 11             if not element:
 12                 return False
 13         return True
 14 
 15 any(iterable)
 16 
 17     Return True if any element of the iterable is true. If the iterable is empty, return False. Equivalent to:
 18 
 19     def any(iterable):
 20         for element in iterable:
 21             if element:
 22                 return True
 23         return False
 24 
 25 ascii(object)
 26 //调用的repr()方法
 27 //类似abs方法的调用
 28     As repr(), return a string containing a printable representation of an object, but escape the non-ASCII characters in the string returned by repr() using \x, \u or \U escapes. This generates a string similar to that returned by repr() in Python 2.
 29 
 30 bin(x)
 31 //二进制
 32     Convert an integer number to a binary string. The result is a valid Python expression. If x is not a Python int object, it has to define an __index__() method that returns an integer.
 33 
 34 class bool([x])
 35 //布尔值
 36     Return a Boolean value, i.e. one of True or False. x is converted using the standard truth testing procedure. If x is false or omitted, this returns False; otherwise it returns True. The bool class is a subclass of int (see Numeric Types — int, float, complex). It cannot be subclassed further. Its only instances are False and True (see Boolean Values).
 37 
 38 class bytearray([source[, encoding[, errors]]])
 39 //返回字节数组
 40     Return a new array of bytes. The bytearray class is a mutable sequence of integers in the range 0 <= x < 256. It has most of the usual methods of mutable sequences, described in Mutable Sequence Types, as well as most methods that the bytes type has, see Bytes and Bytearray Operations.
 41 
 42     The optional source parameter can be used to initialize the array in a few different ways:
 43 
 44         If it is a string, you must also give the encoding (and optionally, errors) parameters; bytearray() then converts the string to bytes using str.encode().
 45         If it is an integer, the array will have that size and will be initialized with null bytes.
 46         If it is an object conforming to the buffer interface, a read-only buffer of the object will be used to initialize the bytes array.
 47         If it is an iterable, it must be an iterable of integers in the range 0 <= x < 256, which are used as the initial contents of the array.
 48 
 49     Without an argument, an array of size 0 is created.
 50 
 51     See also Binary Sequence Types — bytes, bytearray, memoryview and Bytearray Objects.
 52 
 53 class bytes([source[, encoding[, errors]]])
 54 //返回字节
 55     Return a new “bytes” object, which is an immutable sequence of integers in the range 0 <= x < 256. bytes is an immutable version of bytearray – it has the same non-mutating methods and the same indexing and slicing behavior.
 56 
 57     Accordingly, constructor arguments are interpreted as for bytearray().
 58 
 59     Bytes objects can also be created with literals, see String and Bytes literals.
 60 
 61     See also Binary Sequence Types — bytes, bytearray, memoryview, Bytes, and Bytes and Bytearray Operations.
 62 
 63 callable(object)
 64 //查看是否被调用
 65     Return True if the object argument appears callable, False if not. If this returns true, it is still possible that a call fails, but if it is false, calling object will never succeed. Note that classes are callable (calling a class returns a new instance); instances are callable if their class has a __call__() method.
 66 
 67     New in version 3.2: This function was first removed in Python 3.0 and then brought back in Python 3.2.
 68 
 69 chr(i)
 70 //与ord()组合使用，ascii码相互转换
 71     Return the string representing a character whose Unicode code point is the integer i. For example, chr(97) returns the string ‘a‘, while chr(8364) returns the string ‘€‘. This is the inverse of ord().
 72 
 73     The valid range for the argument is from 0 through 1,114,111 (0x10FFFF in base 16). ValueError will be raised if i is outside that range.
 74 
 75 classmethod(function)
 76 //暂未涉及
 77     Return a class method for function.
 78 
 79     A class method receives the class as implicit first argument, just like an instance method receives the instance. To declare a class method, use this idiom:
 80 
 81     class C:
 82         @classmethod
 83         def f(cls, arg1, arg2, ...): ...
 84 
 85     The @classmethod form is a function decorator – see the description of function definitions in Function definitions for details.
 86 
 87     It can be called either on the class (such as C.f()) or on an instance (such as C().f()). The instance is ignored except for its class. If a class method is called for a derived class, the derived class object is passed as the implied first argument.
 88 
 89     Class methods are different than C++ or Java static methods. If you want those, see staticmethod() in this section.
 90 
 91     For more information on class methods, consult the documentation on the standard type hierarchy in The standard type hierarchy.
 92 
 93 
 94 compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)
 95 //编译，未深涉及
 96     Compile the source into a code or AST object. Code objects can be executed by exec() or eval(). source can either be a normal string, a byte string, or an AST object. Refer to the ast module documentation for information on how to work with AST objects.
 97 
 98     The filename argument should give the file from which the code was read; pass some recognizable value if it wasn’t read from a file (‘<string>‘ is commonly used).
 99 
100     The mode argument specifies what kind of code must be compiled; it can be ‘exec‘ if source consists of a sequence of statements, ‘eval‘ if it consists of a single expression, or ‘single‘ if it consists of a single interactive statement (in the latter case, expression statements that evaluate to something other than None will be printed).
101 
102     The optional arguments flags and dont_inherit control which future statements (see PEP 236) affect the compilation of source. If neither is present (or both are zero) the code is compiled with those future statements that are in effect in the code that is calling compile(). If the flags argument is given and dont_inherit is not (or is zero) then the future statements specified by the flags argument are used in addition to those that would be used anyway. If dont_inherit is a non-zero integer then the flags argument is it – the future statements in effect around the call to compile are ignored.
103 
104     Future statements are specified by bits which can be bitwise ORed together to specify multiple statements. The bitfield required to specify a given feature can be found as the compiler_flag attribute on the _Feature instance in the __future__ module.
105 
106     The argument optimize specifies the optimization level of the compiler; the default value of -1 selects the optimization level of the interpreter as given by -O options. Explicit levels are 0 (no optimization; __debug__ is true), 1 (asserts are removed, __debug__ is false) or 2 (docstrings are removed too).
107 
108     This function raises SyntaxError if the compiled source is invalid, and ValueError if the source contains null bytes.
109 
110     If you want to parse Python code into its AST representation, see ast.parse().
111 
112     Note
113 
114     When compiling a string with multi-line code in ‘single‘ or ‘eval‘ mode, input must be terminated by at least one newline character. This is to facilitate detection of incomplete and complete statements in the code module.
115 
116     Changed in version 3.2: Allowed use of Windows and Mac newlines. Also input in ‘exec‘ mode does not have to end in a newline anymore. Added the optimize parameter.
117 
118     Changed in version 3.5: Previously, TypeError was raised when null bytes were encountered in source.
119 
120 class complex([real[, imag]])
121 //复数
122     Return a complex number with the value real + imag*1j or convert a string or number to a complex number. If the first parameter is a string, it will be interpreted as a complex number and the function must be called without a second parameter. The second parameter can never be a string. Each argument may be any numeric type (including complex). If imag is omitted, it defaults to zero and the constructor serves as a numeric conversion like int and float. If both arguments are omitted, returns 0j.
123 
124     Note
125 
126     When converting from a string, the string must not contain whitespace around the central + or - operator. For example, complex(‘1+2j‘) is fine, but complex(‘1 + 2j‘) raises ValueError.
127 
128     The complex type is described in Numeric Types — int, float, complex.
129 
130 delattr(object, name)
131 //反射的时候用，暂未涉及
132     This is a relative of setattr(). The arguments are an object and a string. The string must be the name of one of the object’s attributes. The function deletes the named attribute, provided the object allows it. For example, delattr(x, ‘foobar‘) is equivalent to del x.foobar.
133 
134 class dict(**kwarg)
135 class dict(mapping, **kwarg)
136 class dict(iterable, **kwarg)
137 
138     Create a new dictionary. The dict object is the dictionary class. See dict and Mapping Types — dict for documentation about this class.
139 
140     For other containers see the built-in list, set, and tuple classes, as well as the collections module.
141 
142 dir([object])
143 //
144     Without arguments, return the list of names in the current local scope. With an argument, attempt to return a list of valid attributes for that object.
145 
146     If the object has a method named __dir__(), this method will be called and must return the list of attributes. This allows objects that implement a custom __getattr__() or __getattribute__() function to customize the way dir() reports their attributes.
147 
148     If the object does not provide __dir__(), the function tries its best to gather information from the object’s __dict__ attribute, if defined, and from its type object. The resulting list is not necessarily complete, and may be inaccurate when the object has a custom __getattr__().
149 
150     The default dir() mechanism behaves differently with different types of objects, as it attempts to produce the most relevant, rather than complete, information:
151 
152         If the object is a module object, the list contains the names of the module’s attributes.
153         If the object is a type or class object, the list contains the names of its attributes, and recursively of the attributes of its bases.
154         Otherwise, the list contains the object’s attributes’ names, the names of its class’s attributes, and recursively of the attributes of its class’s base classes.
155 
156     The resulting list is sorted alphabetically. For example:
157     >>>
158 
159     >>> import struct
160     >>> dir()   # show the names in the module namespace
161     [‘__builtins__‘, ‘__name__‘, ‘struct‘]
162     >>> dir(struct)   # show the names in the struct module 
163     [‘Struct‘, ‘__all__‘, ‘__builtins__‘, ‘__cached__‘, ‘__doc__‘, ‘__file__‘,
164      ‘__initializing__‘, ‘__loader__‘, ‘__name__‘, ‘__package__‘,
165      ‘_clearcache‘, ‘calcsize‘, ‘error‘, ‘pack‘, ‘pack_into‘,
166      ‘unpack‘, ‘unpack_from‘]
167     >>> class Shape:
168     ...     def __dir__(self):
169     ...         return [‘area‘, ‘perimeter‘, ‘location‘]
170     >>> s = Shape()
171     >>> dir(s)
172     [‘area‘, ‘location‘, ‘perimeter‘]
173 
174     Note
175 
176     Because dir() is supplied primarily as a convenience for use at an interactive prompt, it tries to supply an interesting set of names more than it tries to supply a rigorously or consistently defined set of names, and its detailed behavior may change across releases. For example, metaclass attributes are not in the result list when the argument is a class.
177 
178 divmod(a, b)
179 
180     Take two (non complex) numbers as arguments and return a pair of numbers consisting of their quotient and remainder when using integer division. With mixed operand types, the rules for binary arithmetic operators apply. For integers, the result is the same as (a // b, a % b). For floating point numbers the result is (q, a % b), where q is usually math.floor(a / b) but may be 1 less than that. In any case q * b + a % b is very close to a, if a % b is non-zero it has the same sign as b, and 0 <= abs(a % b) < abs(b).
181 
182 enumerate(iterable, start=0)
183 
184     Return an enumerate object. iterable must be a sequence, an iterator, or some other object which supports iteration. The __next__() method of the iterator returned by enumerate() returns a tuple containing a count (from start which defaults to 0) and the values obtained from iterating over iterable.
185     >>>
186 
187     >>> seasons = [‘Spring‘, ‘Summer‘, ‘Fall‘, ‘Winter‘]
188     >>> list(enumerate(seasons))
189     [(0, ‘Spring‘), (1, ‘Summer‘), (2, ‘Fall‘), (3, ‘Winter‘)]
190     >>> list(enumerate(seasons, start=1))
191     [(1, ‘Spring‘), (2, ‘Summer‘), (3, ‘Fall‘), (4, ‘Winter‘)]
192 
193     Equivalent to:
194 
195     def enumerate(sequence, start=0):
196         n = start
197         for elem in sequence:
198             yield n, elem
199             n += 1
200 
201 eval(expression, globals=None, locals=None)
202 
203     The arguments are a string and optional globals and locals. If provided, globals must be a dictionary. If provided, locals can be any mapping object.
204 
205     The expression argument is parsed and evaluated as a Python expression (technically speaking, a condition list) using the globals and locals dictionaries as global and local namespace. If the globals dictionary is present and lacks ‘__builtins__’, the current globals are copied into globals before expression is parsed. This means that expression normally has full access to the standard builtins module and restricted environments are propagated. If the locals dictionary is omitted it defaults to the globals dictionary. If both dictionaries are omitted, the expression is executed in the environment where eval() is called. The return value is the result of the evaluated expression. Syntax errors are reported as exceptions. Example:
206     >>>
207 
208     >>> x = 1
209     >>> eval(‘x+1‘)
210     2
211 
212     This function can also be used to execute arbitrary code objects (such as those created by compile()). In this case pass a code object instead of a string. If the code object has been compiled with ‘exec‘ as the mode argument, eval()‘s return value will be None.
213 
214     Hints: dynamic execution of statements is supported by the exec() function. The globals() and locals() functions returns the current global and local dictionary, respectively, which may be useful to pass around for use by eval() or exec().
215 
216     See ast.literal_eval() for a function that can safely evaluate strings with expressions containing only literals.
217 
218 exec(object[, globals[, locals]])
219 
220     This function supports dynamic execution of Python code. object must be either a string or a code object. If it is a string, the string is parsed as a suite of Python statements which is then executed (unless a syntax error occurs). [1] If it is a code object, it is simply executed. In all cases, the code that’s executed is expected to be valid as file input (see the section “File input” in the Reference Manual). Be aware that the return and yield statements may not be used outside of function definitions even within the context of code passed to the exec() function. The return value is None.
221 
222     In all cases, if the optional parts are omitted, the code is executed in the current scope. If only globals is provided, it must be a dictionary, which will be used for both the global and the local variables. If globals and locals are given, they are used for the global and local variables, respectively. If provided, locals can be any mapping object. Remember that at module level, globals and locals are the same dictionary. If exec gets two separate objects as globals and locals, the code will be executed as if it were embedded in a class definition.
223 
224     If the globals dictionary does not contain a value for the key __builtins__, a reference to the dictionary of the built-in module builtins is inserted under that key. That way you can control what builtins are available to the executed code by inserting your own __builtins__ dictionary into globals before passing it to exec().
225 
226     Note
227 
228     The built-in functions globals() and locals() return the current global and local dictionary, respectively, which may be useful to pass around for use as the second and third argument to exec().
229 
230     Note
231 
232     The default locals act as described for function locals() below: modifications to the default locals dictionary should not be attempted. Pass an explicit locals dictionary if you need to see effects of the code on locals after function exec() returns.
233 
234 filter(function, iterable)
235 
236     Construct an iterator from those elements of iterable for which function returns true. iterable may be either a sequence, a container which supports iteration, or an iterator. If function is None, the identity function is assumed, that is, all elements of iterable that are false are removed.
237 
238     Note that filter(function, iterable) is equivalent to the generator expression (item for item in iterable if function(item)) if function is not None and (item for item in iterable if item) if function is None.
239 
240     See itertools.filterfalse() for the complementary function that returns elements of iterable for which function returns false.
241 
242 class float([x])
243 
244     Return a floating point number constructed from a number or string x.
245 
246     If the argument is a string, it should contain a decimal number, optionally preceded by a sign, and optionally embedded in whitespace. The optional sign may be ‘+‘ or ‘-‘; a ‘+‘ sign has no effect on the value produced. The argument may also be a string representing a NaN (not-a-number), or a positive or negative infinity. More precisely, the input must conform to the following grammar after leading and trailing whitespace characters are removed:
247 
248     sign           ::=  "+" | "-"
249     infinity       ::=  "Infinity" | "inf"
250     nan            ::=  "nan"
251     numeric_value  ::=  floatnumber | infinity | nan
252     numeric_string ::=  [sign] numeric_value
253 
254     Here floatnumber is the form of a Python floating-point literal, described in Floating point literals. Case is not significant, so, for example, “inf”, “Inf”, “INFINITY” and “iNfINity” are all acceptable spellings for positive infinity.
255 
256     Otherwise, if the argument is an integer or a floating point number, a floating point number with the same value (within Python’s floating point precision) is returned. If the argument is outside the range of a Python float, an OverflowError will be raised.
257 
258     For a general Python object x, float(x) delegates to x.__float__().
259 
260     If no argument is given, 0.0 is returned.
261 
262     Examples:
263     >>>
264 
265     >>> float(‘+1.23‘)
266     1.23
267     >>> float(‘   -12345\n‘)
268     -12345.0
269     >>> float(‘1e-003‘)
270     0.001
271     >>> float(‘+1E6‘)
272     1000000.0
273     >>> float(‘-Infinity‘)
274     -inf
275 
276     The float type is described in Numeric Types — int, float, complex.
277 
278 format(value[, format_spec])
279 
280     Convert a value to a “formatted” representation, as controlled by format_spec. The interpretation of format_spec will depend on the type of the value argument, however there is a standard formatting syntax that is used by most built-in types: Format Specification Mini-Language.
281 
282     The default format_spec is an empty string which usually gives the same effect as calling str(value).
283 
284     A call to format(value, format_spec) is translated to type(value).__format__(value, format_spec) which bypasses the instance dictionary when searching for the value’s __format__() method. A TypeError exception is raised if the method search reaches object and the format_spec is non-empty, or if either the format_spec or the return value are not strings.
285 
286     Changed in version 3.4: object().__format__(format_spec) raises TypeError if format_spec is not an empty string.
287 
288 class frozenset([iterable])
289 
290     Return a new frozenset object, optionally with elements taken from iterable. frozenset is a built-in class. See frozenset and Set Types — set, frozenset for documentation about this class.
291 
292     For other containers see the built-in set, list, tuple, and dict classes, as well as the collections module.
293 
294 getattr(object, name[, default])
295 
296     Return the value of the named attribute of object. name must be a string. If the string is the name of one of the object’s attributes, the result is the value of that attribute. For example, getattr(x, ‘foobar‘) is equivalent to x.foobar. If the named attribute does not exist, default is returned if provided, otherwise AttributeError is raised.
297 
298 globals()
299 
300     Return a dictionary representing the current global symbol table. This is always the dictionary of the current module (inside a function or method, this is the module where it is defined, not the module from which it is called).
301 
302 hasattr(object, name)
303 
304     The arguments are an object and a string. The result is True if the string is the name of one of the object’s attributes, False if not. (This is implemented by calling getattr(object, name) and seeing whether it raises an AttributeError or not.)
305 
306 hash(object)
307 
308         Return the hash value of the object (if it has one). Hash values are integers. They are used to quickly compare dictionary keys during a dictionary lookup. Numeric values that compare equal have the same hash value (even if they are of different types, as is the case for 1 and 1.0).
309 
310     Note
311 
312     For object’s with custom __hash__() methods, note that hash() truncates the return value based on the bit width of the host machine. See __hash__() for details.
313 
314 help([object])
315 
316     Invoke the built-in help system. (This function is intended for interactive use.) If no argument is given, the interactive help system starts on the interpreter console. If the argument is a string, then the string is looked up as the name of a module, function, class, method, keyword, or documentation topic, and a help page is printed on the console. If the argument is any other kind of object, a help page on the object is generated.
317 
318     This function is added to the built-in namespace by the site module.
319 
320     Changed in version 3.4: Changes to pydoc and inspect mean that the reported signatures for callables are now more comprehensive and consistent.
321 
322 hex(x)
323 
324     Convert an integer number to a lowercase hexadecimal string prefixed with “0x”, for example:
325     >>>
326 
327     >>> hex(255)
328     ‘0xff‘
329     >>> hex(-42)
330     ‘-0x2a‘
331 
332     If x is not a Python int object, it has to define an __index__() method that returns an integer.
333 
334     See also int() for converting a hexadecimal string to an integer using a base of 16.
335 
336     Note
337 
338     To obtain a hexadecimal string representation for a float, use the float.hex() method.
339 
340 id(object)
341 
342     Return the “identity” of an object. This is an integer which is guaranteed to be unique and constant for this object during its lifetime. Two objects with non-overlapping lifetimes may have the same id() value.
343 
344     CPython implementation detail: This is the address of the object in memory.
345 
346 input([prompt])
347 
348     If the prompt argument is present, it is written to standard output without a trailing newline. The function then reads a line from input, converts it to a string (stripping a trailing newline), and returns that. When EOF is read, EOFError is raised. Example:
349     >>>
350 
351     >>> s = input(‘--> ‘)  
352     --> Monty Python‘s Flying Circus
353     >>> s  
354     "Monty Python‘s Flying Circus"
355 
356     If the readline module was loaded, then input() will use it to provide elaborate line editing and history features.
357 
358 class int(x=0)
359 class int(x, base=10)
360 
361     Return an integer object constructed from a number or string x, or return 0 if no arguments are given. If x is a number, return x.__int__(). For floating point numbers, this truncates towards zero.
362 
363     If x is not a number or if base is given, then x must be a string, bytes, or bytearray instance representing an integer literal in radix base. Optionally, the literal can be preceded by + or - (with no space in between) and surrounded by whitespace. A base-n literal consists of the digits 0 to n-1, with a to z (or A to Z) having values 10 to 35. The default base is 10. The allowed values are 0 and 2-36. Base-2, -8, and -16 literals can be optionally prefixed with 0b/0B, 0o/0O, or 0x/0X, as with integer literals in code. Base 0 means to interpret exactly as a code literal, so that the actual base is 2, 8, 10, or 16, and so that int(‘010‘, 0) is not legal, while int(‘010‘) is, as well as int(‘010‘, 8).
364 
365     The integer type is described in Numeric Types — int, float, complex.
366 
367     Changed in version 3.4: If base is not an instance of int and the base object has a base.__index__ method, that method is called to obtain an integer for the base. Previous versions used base.__int__ instead of base.__index__.
368 
369 isinstance(object, classinfo)
370 
371     Return true if the object argument is an instance of the classinfo argument, or of a (direct, indirect or virtual) subclass thereof. If object is not an object of the given type, the function always returns false. If classinfo is a tuple of type objects (or recursively, other such tuples), return true if object is an instance of any of the types. If classinfo is not a type or tuple of types and such tuples, a TypeError exception is raised.
372 
373 issubclass(class, classinfo)
374 
375     Return true if class is a subclass (direct, indirect or virtual) of classinfo. A class is considered a subclass of itself. classinfo may be a tuple of class objects, in which case every entry in classinfo will be checked. In any other case, a TypeError exception is raised.
376 
377 iter(object[, sentinel])
378 
379     Return an iterator object. The first argument is interpreted very differently depending on the presence of the second argument. Without a second argument, object must be a collection object which supports the iteration protocol (the __iter__() method), or it must support the sequence protocol (the __getitem__() method with integer arguments starting at 0). If it does not support either of those protocols, TypeError is raised. If the second argument, sentinel, is given, then object must be a callable object. The iterator created in this case will call object with no arguments for each call to its __next__() method; if the value returned is equal to sentinel, StopIteration will be raised, otherwise the value will be returned.
380 
381     See also Iterator Types.
382 
383     One useful application of the second form of iter() is to read lines of a file until a certain line is reached. The following example reads a file until the readline() method returns an empty string:
384 
385     with open(‘mydata.txt‘) as fp:
386         for line in iter(fp.readline, ‘‘):
387             process_line(line)
388 
389 len(s)
390 
391     Return the length (the number of items) of an object. The argument may be a sequence (such as a string, bytes, tuple, list, or range) or a collection (such as a dictionary, set, or frozen set).
392 
393 class list([iterable])
394 
395     Rather than being a function, list is actually a mutable sequence type, as documented in Lists and Sequence Types — list, tuple, range.
396 
397 locals()
398 
399     Update and return a dictionary representing the current local symbol table. Free variables are returned by locals() when it is called in function blocks, but not in class blocks.
400 
401     Note
402 
403     The contents of this dictionary should not be modified; changes may not affect the values of local and free variables used by the interpreter.
404 
405 map(function, iterable, ...)
406 
407     Return an iterator that applies function to every item of iterable, yielding the results. If additional iterable arguments are passed, function must take that many arguments and is applied to the items from all iterables in parallel. With multiple iterables, the iterator stops when the shortest iterable is exhausted. For cases where the function inputs are already arranged into argument tuples, see itertools.starmap().
408 
409 max(iterable, *[, key, default])
410 max(arg1, arg2, *args[, key])
411 
412     Return the largest item in an iterable or the largest of two or more arguments.
413 
414     If one positional argument is provided, it should be an iterable. The largest item in the iterable is returned. If two or more positional arguments are provided, the largest of the positional arguments is returned.
415 
416     There are two optional keyword-only arguments. The key argument specifies a one-argument ordering function like that used for list.sort(). The default argument specifies an object to return if the provided iterable is empty. If the iterable is empty and default is not provided, a ValueError is raised.
417 
418     If multiple items are maximal, the function returns the first one encountered. This is consistent with other sort-stability preserving tools such as sorted(iterable, key=keyfunc, reverse=True)[0] and heapq.nlargest(1, iterable, key=keyfunc).
419 
420     New in version 3.4: The default keyword-only argument.
421 
422 memoryview(obj)
423 
424     Return a “memory view” object created from the given argument. See Memory Views for more information.
425 
426 min(iterable, *[, key, default])
427 min(arg1, arg2, *args[, key])
428 
429     Return the smallest item in an iterable or the smallest of two or more arguments.
430 
431     If one positional argument is provided, it should be an iterable. The smallest item in the iterable is returned. If two or more positional arguments are provided, the smallest of the positional arguments is returned.
432 
433     There are two optional keyword-only arguments. The key argument specifies a one-argument ordering function like that used for list.sort(). The default argument specifies an object to return if the provided iterable is empty. If the iterable is empty and default is not provided, a ValueError is raised.
434 
435     If multiple items are minimal, the function returns the first one encountered. This is consistent with other sort-stability preserving tools such as sorted(iterable, key=keyfunc)[0] and heapq.nsmallest(1, iterable, key=keyfunc).
436 
437     New in version 3.4: The default keyword-only argument.
438 
439 next(iterator[, default])
440 
441     Retrieve the next item from the iterator by calling its __next__() method. If default is given, it is returned if the iterator is exhausted, otherwise StopIteration is raised.
442 
443 class object
444 
445     Return a new featureless object. object is a base for all classes. It has the methods that are common to all instances of Python classes. This function does not accept any arguments.
446 
447     Note
448 
449     object does not have a __dict__, so you can’t assign arbitrary attributes to an instance of the object class.
450 
451 oct(x)
452 
453     Convert an integer number to an octal string. The result is a valid Python expression. If x is not a Python int object, it has to define an __index__() method that returns an integer.
454 
455 open(file, mode=‘r‘, buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)
456 
457     Open file and return a corresponding file object. If the file cannot be opened, an OSError is raised.
458 
459     file is either a string or bytes object giving the pathname (absolute or relative to the current working directory) of the file to be opened or an integer file descriptor of the file to be wrapped. (If a file descriptor is given, it is closed when the returned I/O object is closed, unless closefd is set to False.)
460 
461     mode is an optional string that specifies the mode in which the file is opened. It defaults to ‘r‘ which means open for reading in text mode. Other common values are ‘w‘ for writing (truncating the file if it already exists), ‘x‘ for exclusive creation and ‘a‘ for appending (which on some Unix systems, means that all writes append to the end of the file regardless of the current seek position). In text mode, if encoding is not specified the encoding used is platform dependent: locale.getpreferredencoding(False) is called to get the current locale encoding. (For reading and writing raw bytes use binary mode and leave encoding unspecified.) The available modes are:
462     Character     Meaning
463     ‘r‘     open for reading (default)
464     ‘w‘     open for writing, truncating the file first
465     ‘x‘     open for exclusive creation, failing if the file already exists
466     ‘a‘     open for writing, appending to the end of the file if it exists
467     ‘b‘     binary mode
468     ‘t‘     text mode (default)
469     ‘+‘     open a disk file for updating (reading and writing)
470     ‘U‘     universal newlines mode (deprecated)
471 
472     The default mode is ‘r‘ (open for reading text, synonym of ‘rt‘). For binary read-write access, the mode ‘w+b‘ opens and truncates the file to 0 bytes. ‘r+b‘ opens the file without truncation.
473 
474     As mentioned in the Overview, Python distinguishes between binary and text I/O. Files opened in binary mode (including ‘b‘ in the mode argument) return contents as bytes objects without any decoding. In text mode (the default, or when ‘t‘ is included in the mode argument), the contents of the file are returned as str, the bytes having been first decoded using a platform-dependent encoding or using the specified encoding if given.
475 
476     Note
477 
478     Python doesn’t depend on the underlying operating system’s notion of text files; all the processing is done by Python itself, and is therefore platform-independent.
479 
480     buffering is an optional integer used to set the buffering policy. Pass 0 to switch buffering off (only allowed in binary mode), 1 to select line buffering (only usable in text mode), and an integer > 1 to indicate the size in bytes of a fixed-size chunk buffer. When no buffering argument is given, the default buffering policy works as follows:
481 
482         Binary files are buffered in fixed-size chunks; the size of the buffer is chosen using a heuristic trying to determine the underlying device’s “block size” and falling back on io.DEFAULT_BUFFER_SIZE. On many systems, the buffer will typically be 4096 or 8192 bytes long.
483         “Interactive” text files (files for which isatty() returns True) use line buffering. Other text files use the policy described above for binary files.
484 
485     encoding is the name of the encoding used to decode or encode the file. This should only be used in text mode. The default encoding is platform dependent (whatever locale.getpreferredencoding() returns), but any text encoding supported by Python can be used. See the codecs module for the list of supported encodings.
486 
487     errors is an optional string that specifies how encoding and decoding errors are to be handled–this cannot be used in binary mode. A variety of standard error handlers are available (listed under Error Handlers), though any error handling name that has been registered with codecs.register_error() is also valid. The standard names include:
488 
489         ‘strict‘ to raise a ValueError exception if there is an encoding error. The default value of None has the same effect.
490         ‘ignore‘ ignores errors. Note that ignoring encoding errors can lead to data loss.
491         ‘replace‘ causes a replacement marker (such as ‘?‘) to be inserted where there is malformed data.
492         ‘surrogateescape‘ will represent any incorrect bytes as code points in the Unicode Private Use Area ranging from U+DC80 to U+DCFF. These private code points will then be turned back into the same bytes when the surrogateescape error handler is used when writing data. This is useful for processing files in an unknown encoding.
493         ‘xmlcharrefreplace‘ is only supported when writing to a file. Characters not supported by the encoding are replaced with the appropriate XML character reference &#nnn;.
494         ‘backslashreplace‘ replaces malformed data by Python’s backslashed escape sequences.
495         ‘namereplace‘ (also only supported when writing) replaces unsupported characters with \N{...} escape sequences.
496 
497     newline controls how universal newlines mode works (it only applies to text mode). It can be None, ‘‘, ‘\n‘, ‘\r‘, and ‘\r\n‘. It works as follows:
498 
499         When reading input from the stream, if newline is None, universal newlines mode is enabled. Lines in the input can end in ‘\n‘, ‘\r‘, or ‘\r\n‘, and these are translated into ‘\n‘ before being returned to the caller. If it is ‘‘, universal newlines mode is enabled, but line endings are returned to the caller untranslated. If it has any of the other legal values, input lines are only terminated by the given string, and the line ending is returned to the caller untranslated.
500         When writing output to the stream, if newline is None, any ‘\n‘ characters written are translated to the system default line separator, os.linesep. If newline is ‘‘ or ‘\n‘, no translation takes place. If newline is any of the other legal values, any ‘\n‘ characters written are translated to the given string.
501 
502     If closefd is False and a file descriptor rather than a filename was given, the underlying file descriptor will be kept open when the file is closed. If a filename is given closefd must be True (the default) otherwise an error will be raised.
503 
504     A custom opener can be used by passing a callable as opener. The underlying file descriptor for the file object is then obtained by calling opener with (file, flags). opener must return an open file descriptor (passing os.open as opener results in functionality similar to passing None).
505 
506     The newly created file is non-inheritable.
507 
508     The following example uses the dir_fd parameter of the os.open() function to open a file relative to a given directory:
509     >>>
510 
511     >>> import os
512     >>> dir_fd = os.open(‘somedir‘, os.O_RDONLY)
513     >>> def opener(path, flags):
514     ...     return os.open(path, flags, dir_fd=dir_fd)
515     ...
516     >>> with open(‘spamspam.txt‘, ‘w‘, opener=opener) as f:
517     ...     print(‘This will be written to somedir/spamspam.txt‘, file=f)
518     ...
519     >>> os.close(dir_fd)  # don‘t leak a file descriptor
520 
521     The type of file object returned by the open() function depends on the mode. When open() is used to open a file in a text mode (‘w‘, ‘r‘, ‘wt‘, ‘rt‘, etc.), it returns a subclass of io.TextIOBase (specifically io.TextIOWrapper). When used to open a file in a binary mode with buffering, the returned class is a subclass of io.BufferedIOBase. The exact class varies: in read binary mode, it returns an io.BufferedReader; in write binary and append binary modes, it returns an io.BufferedWriter, and in read/write mode, it returns an io.BufferedRandom. When buffering is disabled, the raw stream, a subclass of io.RawIOBase, io.FileIO, is returned.
522 
523     See also the file handling modules, such as, fileinput, io (where open() is declared), os, os.path, tempfile, and shutil.
524 
525     Changed in version 3.3: The opener parameter was added. The ‘x‘ mode was added. IOError used to be raised, it is now an alias of OSError. FileExistsError is now raised if the file opened in exclusive creation mode (‘x‘) already exists.
526 
527     Changed in version 3.4: The file is now non-inheritable.
528 
529     Deprecated since version 3.4, will be removed in version 4.0: The ‘U‘ mode.
530 
531     Changed in version 3.5: If the system call is interrupted and the signal handler does not raise an exception, the function now retries the system call instead of raising an InterruptedError exception (see PEP 475 for the rationale).
532 
533     Changed in version 3.5: The ‘namereplace‘ error handler was added.
534 
535 ord(c)
536 
537     Given a string representing one Unicode character, return an integer representing the Unicode code point of that character. For example, ord(‘a‘) returns the integer 97 and ord(‘€‘) (Euro sign) returns 8364. This is the inverse of chr().
538 
539 pow(x, y[, z])
540 
541     Return x to the power y; if z is present, return x to the power y, modulo z (computed more efficiently than pow(x, y) % z). The two-argument form pow(x, y) is equivalent to using the power operator: x**y.
542 
543     The arguments must have numeric types. With mixed operand types, the coercion rules for binary arithmetic operators apply. For int operands, the result has the same type as the operands (after coercion) unless the second argument is negative; in that case, all arguments are converted to float and a float result is delivered. For example, 10**2 returns 100, but 10**-2 returns 0.01. If the second argument is negative, the third argument must be omitted. If z is present, x and y must be of integer types, and y must be non-negative.
544 
545 print(*objects, sep=‘ ‘, end=‘\n‘, file=sys.stdout, flush=False)
546 
547     Print objects to the text stream file, separated by sep and followed by end. sep, end and file, if present, must be given as keyword arguments.
548 
549     All non-keyword arguments are converted to strings like str() does and written to the stream, separated by sep and followed by end. Both sep and end must be strings; they can also be None, which means to use the default values. If no objects are given, print() will just write end.
550 
551     The file argument must be an object with a write(string) method; if it is not present or None, sys.stdout will be used. Since printed arguments are converted to text strings, print() cannot be used with binary mode file objects. For these, use file.write(...) instead.
552 
553     Whether output is buffered is usually determined by file, but if the flush keyword argument is true, the stream is forcibly flushed.
554 
555     Changed in version 3.3: Added the flush keyword argument.
556 
557 class property(fget=None, fset=None, fdel=None, doc=None)
558 
559     Return a property attribute.
560 
561     fget is a function for getting an attribute value. fset is a function for setting an attribute value. fdel is a function for deleting an attribute value. And doc creates a docstring for the attribute.
562 
563     A typical use is to define a managed attribute x:
564 
565     class C:
566         def __init__(self):
567             self._x = None
568 
569         def getx(self):
570             return self._x
571 
572         def setx(self, value):
573             self._x = value
574 
575         def delx(self):
576             del self._x
577 
578         x = property(getx, setx, delx, "I‘m the ‘x‘ property.")
579 
580     If c is an instance of C, c.x will invoke the getter, c.x = value will invoke the setter and del c.x the deleter.
581 
582     If given, doc will be the docstring of the property attribute. Otherwise, the property will copy fget‘s docstring (if it exists). This makes it possible to create read-only properties easily using property() as a decorator:
583 
584     class Parrot:
585         def __init__(self):
586             self._voltage = 100000
587 
588         @property
589         def voltage(self):
590             """Get the current voltage."""
591             return self._voltage
592 
593     The @property decorator turns the voltage() method into a “getter” for a read-only attribute with the same name, and it sets the docstring for voltage to “Get the current voltage.”
594 
595     A property object has getter, setter, and deleter methods usable as decorators that create a copy of the property with the corresponding accessor function set to the decorated function. This is best explained with an example:
596 
597     class C:
598         def __init__(self):
599             self._x = None
600 
601         @property
602         def x(self):
603             """I‘m the ‘x‘ property."""
604             return self._x
605 
606         @x.setter
607         def x(self, value):
608             self._x = value
609 
610         @x.deleter
611         def x(self):
612             del self._x
613 
614     This code is exactly equivalent to the first example. Be sure to give the additional functions the same name as the original property (x in this case.)
615 
616     The returned property object also has the attributes fget, fset, and fdel corresponding to the constructor arguments.
617 
618     Changed in version 3.5: The docstrings of property objects are now writeable.
619 
620 range(stop)
621 range(start, stop[, step])
622 
623     Rather than being a function, range is actually an immutable sequence type, as documented in Ranges and Sequence Types — list, tuple, range.
624 
625 repr(object)
626 
627     Return a string containing a printable representation of an object. For many types, this function makes an attempt to return a string that would yield an object with the same value when passed to eval(), otherwise the representation is a string enclosed in angle brackets that contains the name of the type of the object together with additional information often including the name and address of the object. A class can control what this function returns for its instances by defining a __repr__() method.
628 
629 reversed(seq)
630 
631     Return a reverse iterator. seq must be an object which has a __reversed__() method or supports the sequence protocol (the __len__() method and the __getitem__() method with integer arguments starting at 0).
632 
633 round(number[, ndigits])
634 
635     Return the floating point value number rounded to ndigits digits after the decimal point. If ndigits is omitted, it returns the nearest integer to its input. Delegates to number.__round__(ndigits).
636 
637     For the built-in types supporting round(), values are rounded to the closest multiple of 10 to the power minus ndigits; if two multiples are equally close, rounding is done toward the even choice (so, for example, both round(0.5) and round(-0.5) are 0, and round(1.5) is 2). The return value is an integer if called with one argument, otherwise of the same type as number.
638 
639     Note
640 
641     The behavior of round() for floats can be surprising: for example, round(2.675, 2) gives 2.67 instead of the expected 2.68. This is not a bug: it’s a result of the fact that most decimal fractions can’t be represented exactly as a float. See Floating Point Arithmetic: Issues and Limitations for more information.
642 
643 class set([iterable])
644 
645     Return a new set object, optionally with elements taken from iterable. set is a built-in class. See set and Set Types — set, frozenset for documentation about this class.
646 
647     For other containers see the built-in frozenset, list, tuple, and dict classes, as well as the collections module.
648 
649 setattr(object, name, value)
650 
651     This is the counterpart of getattr(). The arguments are an object, a string and an arbitrary value. The string may name an existing attribute or a new attribute. The function assigns the value to the attribute, provided the object allows it. For example, setattr(x, ‘foobar‘, 123) is equivalent to x.foobar = 123.
652 
653 class slice(stop)
654 class slice(start, stop[, step])
655 
656     Return a slice object representing the set of indices specified by range(start, stop, step). The start and step arguments default to None. Slice objects have read-only data attributes start, stop and step which merely return the argument values (or their default). They have no other explicit functionality; however they are used by Numerical Python and other third party extensions. Slice objects are also generated when extended indexing syntax is used. For example: a[start:stop:step] or a[start:stop, i]. See itertools.islice() for an alternate version that returns an iterator.
657 
658 sorted(iterable[, key][, reverse])
659 
660     Return a new sorted list from the items in iterable.
661 
662     Has two optional arguments which must be specified as keyword arguments.
663 
664     key specifies a function of one argument that is used to extract a comparison key from each list element: key=str.lower. The default value is None (compare the elements directly).
665 
666     reverse is a boolean value. If set to True, then the list elements are sorted as if each comparison were reversed.
667 
668     Use functools.cmp_to_key() to convert an old-style cmp function to a key function.
669 
670     The built-in sorted() function is guaranteed to be stable. A sort is stable if it guarantees not to change the relative order of elements that compare equal — this is helpful for sorting in multiple passes (for example, sort by department, then by salary grade).
671 
672     For sorting examples and a brief sorting tutorial, see Sorting HOW TO.
673 
674 staticmethod(function)
675 
676     Return a static method for function.
677 
678     A static method does not receive an implicit first argument. To declare a static method, use this idiom:
679 
680     class C:
681         @staticmethod
682         def f(arg1, arg2, ...): ...
683 
684     The @staticmethod form is a function decorator – see the description of function definitions in Function definitions for details.
685 
686     It can be called either on the class (such as C.f()) or on an instance (such as C().f()). The instance is ignored except for its class.
687 
688     Static methods in Python are similar to those found in Java or C++. Also see classmethod() for a variant that is useful for creating alternate class constructors.
689 
690     For more information on static methods, consult the documentation on the standard type hierarchy in The standard type hierarchy.
691 
692 class str(object=‘‘)
693 class str(object=b‘‘, encoding=‘utf-8‘, errors=‘strict‘)
694 
695     Return a str version of object. See str() for details.
696 
697     str is the built-in string class. For general information about strings, see Text Sequence Type — str.
698 
699 sum(iterable[, start])
700 
701     Sums start and the items of an iterable from left to right and returns the total. start defaults to 0. The iterable‘s items are normally numbers, and the start value is not allowed to be a string.
702 
703     For some use cases, there are good alternatives to sum(). The preferred, fast way to concatenate a sequence of strings is by calling ‘‘.join(sequence). To add floating point values with extended precision, see math.fsum(). To concatenate a series of iterables, consider using itertools.chain().
704 
705 super([type[, object-or-type]])
706 
707     Return a proxy object that delegates method calls to a parent or sibling class of type. This is useful for accessing inherited methods that have been overridden in a class. The search order is same as that used by getattr() except that the type itself is skipped.
708 
709     The __mro__ attribute of the type lists the method resolution search order used by both getattr() and super(). The attribute is dynamic and can change whenever the inheritance hierarchy is updated.
710 
711     If the second argument is omitted, the super object returned is unbound. If the second argument is an object, isinstance(obj, type) must be true. If the second argument is a type, issubclass(type2, type) must be true (this is useful for classmethods).
712 
713     There are two typical use cases for super. In a class hierarchy with single inheritance, super can be used to refer to parent classes without naming them explicitly, thus making the code more maintainable. This use closely parallels the use of super in other programming languages.
714 
715     The second use case is to support cooperative multiple inheritance in a dynamic execution environment. This use case is unique to Python and is not found in statically compiled languages or languages that only support single inheritance. This makes it possible to implement “diamond diagrams” where multiple base classes implement the same method. Good design dictates that this method have the same calling signature in every case (because the order of calls is determined at runtime, because that order adapts to changes in the class hierarchy, and because that order can include sibling classes that are unknown prior to runtime).
716 
717     For both use cases, a typical superclass call looks like this:
718 
719     class C(B):
720         def method(self, arg):
721             super().method(arg)    # This does the same thing as:
722                                    # super(C, self).method(arg)
723 
724     Note that super() is implemented as part of the binding process for explicit dotted attribute lookups such as super().__getitem__(name). It does so by implementing its own __getattribute__() method for searching classes in a predictable order that supports cooperative multiple inheritance. Accordingly, super() is undefined for implicit lookups using statements or operators such as super()[name].
725 
726     Also note that, aside from the zero argument form, super() is not limited to use inside methods. The two argument form specifies the arguments exactly and makes the appropriate references. The zero argument form only works inside a class definition, as the compiler fills in the necessary details to correctly retrieve the class being defined, as well as accessing the current instance for ordinary methods.
727 
728     For practical suggestions on how to design cooperative classes using super(), see guide to using super().
729 
730 tuple([iterable])
731 
732     Rather than being a function, tuple is actually an immutable sequence type, as documented in Tuples and Sequence Types — list, tuple, range.
733 
734 class type(object)
735 class type(name, bases, dict)
736 
737     With one argument, return the type of an object. The return value is a type object and generally the same object as returned by object.__class__.
738 
739     The isinstance() built-in function is recommended for testing the type of an object, because it takes subclasses into account.
740 
741     With three arguments, return a new type object. This is essentially a dynamic form of the class statement. The name string is the class name and becomes the __name__ attribute; the bases tuple itemizes the base classes and becomes the __bases__ attribute; and the dict dictionary is the namespace containing definitions for class body and is copied to a standard dictionary to become the __dict__ attribute. For example, the following two statements create identical type objects:
742     >>>
743 
744     >>> class X:
745     ...     a = 1
746     ...
747     >>> X = type(‘X‘, (object,), dict(a=1))
748 
749     See also Type Objects.
750 
751 vars([object])
752 
753     Return the __dict__ attribute for a module, class, instance, or any other object with a __dict__ attribute.
754 
755     Objects such as modules and instances have an updateable __dict__ attribute; however, other objects may have write restrictions on their __dict__ attributes (for example, classes use a types.MappingProxyType to prevent direct dictionary updates).
756 
757     Without an argument, vars() acts like locals(). Note, the locals dictionary is only useful for reads since updates to the locals dictionary are ignored.
758 
759 zip(*iterables)
760 
761     Make an iterator that aggregates elements from each of the iterables.
762 
763     Returns an iterator of tuples, where the i-th tuple contains the i-th element from each of the argument sequences or iterables. The iterator stops when the shortest input iterable is exhausted. With a single iterable argument, it returns an iterator of 1-tuples. With no arguments, it returns an empty iterator. Equivalent to:
764 
765     def zip(*iterables):
766         # zip(‘ABCD‘, ‘xy‘) --> Ax By
767         sentinel = object()
768         iterators = [iter(it) for it in iterables]
769         while iterators:
770             result = []
771             for it in iterators:
772                 elem = next(it, sentinel)
773                 if elem is sentinel:
774                     return
775                 result.append(elem)
776             yield tuple(result)
777 
778     The left-to-right evaluation order of the iterables is guaranteed. This makes possible an idiom for clustering a data series into n-length groups using zip(*[iter(s)]*n). This repeats the same iterator n times so that each output tuple has the result of n calls to the iterator. This has the effect of dividing the input into n-length chunks.
779 
780     zip() should only be used with unequal length inputs when you don’t care about trailing, unmatched values from the longer iterables. If those values are important, use itertools.zip_longest() instead.
781 
782     zip() in conjunction with the * operator can be used to unzip a list:
783     >>>
784 
785     >>> x = [1, 2, 3]
786     >>> y = [4, 5, 6]
787     >>> zipped = zip(x, y)
788     >>> list(zipped)
789     [(1, 4), (2, 5), (3, 6)]
790     >>> x2, y2 = zip(*zip(x, y))
791     >>> x == list(x2) and y == list(y2)
792     True
793 
794 __import__(name, globals=None, locals=None, fromlist=(), level=0)
795 
796     Note
797 
798     This is an advanced function that is not needed in everyday Python programming, unlike importlib.import_module().
799 
800     This function is invoked by the import statement. It can be replaced (by importing the builtins module and assigning to builtins.__import__) in order to change semantics of the import statement, but doing so is strongly discouraged as it is usually simpler to use import hooks (see PEP 302) to attain the same goals and does not cause issues with code which assumes the default import implementation is in use. Direct use of __import__() is also discouraged in favor of importlib.import_module().
801 
802     The function imports the module name, potentially using the given globals and locals to determine how to interpret the name in a package context. The fromlist gives the names of objects or submodules that should be imported from the module given by name. The standard implementation does not use its locals argument at all, and uses its globals only to determine the package context of the import statement.
803 
804     level specifies whether to use absolute or relative imports. 0 (the default) means only perform absolute imports. Positive values for level indicate the number of parent directories to search relative to the directory of the module calling __import__() (see PEP 328 for the details).
805 
806     When the name variable is of the form package.module, normally, the top-level package (the name up till the first dot) is returned, not the module named by name. However, when a non-empty fromlist argument is given, the module named by name is returned.
807 
808     For example, the statement import spam results in bytecode resembling the following code:
809 
810     spam = __import__(‘spam‘, globals(), locals(), [], 0)
811 
812     The statement import spam.ham results in this call:
813 
814     spam = __import__(‘spam.ham‘, globals(), locals(), [], 0)
815 
816     Note how __import__() returns the toplevel module here because this is the object that is bound to a name by the import statement.
817 
818     On the other hand, the statement from spam.ham import eggs, sausage as saus results in
819 
820     _temp = __import__(‘spam.ham‘, globals(), locals(), [‘eggs‘, ‘sausage‘], 0)
821     eggs = _temp.eggs
822     saus = _temp.sausage
823 
824     Here, the spam.ham module is returned from __import__(). From this object, the names to import are retrieved and assigned to their respective names.
825 
826     If you simply want to import a module (potentially within a package) by name, use importlib.import_module().
827 
828     Changed in version 3.3: Negative values for level are no longer supported (which also changes the default value to 0).
829 
830 Footnotes
831 [1]    Note that the parser only accepts the Unix-style end of line convention. If you are reading the code from a file, make sure to use newline conversion mode to convert Windows or Mac-style newlines.