Python基础入门（三）深浅拷贝、函数、内置函数、文件处理、三元运算、递归

 1 import copy
 2 #定义变量   数字、字符串
 3 n1 = 123
 4 #n1 = ‘nick‘
 5 print(id(n1))
 6  
 7 #赋值
 8 n2 = n1
 9 print(id(n2))
10  
11 #浅拷贝
12 n3 = copy.copy(n1)
13 print(id(n3))
14  
15 #深拷贝
16 n4 = copy.deepcopy(n1)
17 print(id(n4))

 1 import copy
 2 
 3 l1 = [10,‘a1‘,[110,111],‘ds‘,]
 4 l2 = copy.copy(l1)  #浅拷贝
 5 
 6 print(l1)
 7 print(l2)
 8 l1[1] = 11  #改变L1的值
 9 l1[2][0] = 1111  #改变l1内嵌列表的值
10 print(l1)
11 print(l2)
12 print(id(l1))
13 print(id(l2))
14 print(id(l1[2][0]))
15 print(id(l2[2][0]))
16 
17 
18 #[10, ‘a1‘, [110, 111], ‘ds‘]
19 #[10, ‘a1‘, [110, 111], ‘ds‘]
20 #通过下面的结果对比，发现浅拷贝对于内嵌多层数据类型的操作，如果多层数据类型值改变，浅拷贝的对象也会跟着改变
21 #[10, 11, [1111, 111], ‘ds‘]
22 #[10, ‘a1‘, [1111, 111], ‘ds‘]
23 
24 #4315829896
25 #4315843720
26 
27 #4312813392
28 #4312813392

import copy

l1 = [10,‘a1‘,[110,111],‘ds‘,]
l2 = copy.deepcopy(l1)

print(l1)
print(l2)
l1[1] = 11  #改变L1的值
l1[2][0] = 1111  #改变l1内层数据的值
print(l1)
print(l2)
print(id(l1))
print(id(l2))
print(id(l1[2][0]))
print(id(l2[2][0]))

#[10, ‘a1‘, [110, 111], ‘ds‘]
#[10, ‘a1‘, [110, 111], ‘ds‘]
#结合上面的例子进行对比发现，对于深层拷贝，内嵌多层的数据类型的值，被改变，不会影响到另一方拷贝或被拷贝的对象
#[10, 11, [1111, 111], ‘ds‘]
#[10, ‘a1‘, [110, 111], ‘ds‘]

#4315829576
#4315829896

#4312813392
#4297541440

 1 #定义函数
 2 #n 叫做函数 name 的形式参数，简称：形参
 3 
 4 def name(n):
 5     print(n)
 6 
 7 #执行函数 
 8 #‘nick‘ 叫做函数 name 的实际参数，简称：实参
 9 
10 name(‘nick‘)

def func(name, age = 18):
    print("%s:%s")%(name,age)

# 指定参数
func(‘nick‘, 19)
# 使用默认参数
func(‘nick‘)

注：默认参数需要放在参数列表最后

def func(*args):
    print args

# 执行方式一
func(11,22,33,55,66)

# 执行方式二
li = [11,22,33,55,66]
func(*li)

def func(**kwargs):
    print kwargs


# 执行方式一
func(name＝‘nick‘,age=18)

# 执行方式二
li = {‘name‘:‘nick‘, age:18, ‘job‘:‘pythoner‘}
func(**li)

def hi(a,*args,**kwargs):
    print(a,type(a))
    print(args,type(args))
    print(kwargs,type(kwargs))
hi(11,22,33,k1=‘nick‘,k2=‘jenny‘)

def mail(主题,邮件内容=‘test‘,收件人=‘1104817655@qq.com‘):
    import smtplib
    from email.mime.text import MIMEText
    from email.utils import formataddr

    msg = MIMEText(邮件内容, ‘plain‘, ‘utf-8‘)
    msg[‘From‘] = formataddr(["发件人", ‘发件人地址‘])
    msg[‘To‘] = formataddr(["收件人", ‘630571017@qq.com‘])
    msg[‘Subject‘] = 主题

    server = smtplib.SMTP("smtp.126.com", 25)
    server.login("登录邮箱账号", "邮箱密码")
    server.sendmail(‘发件邮箱地址账号‘, [收件人地址, ], msg.as_string())
    server.quit()

mail(‘我是主题‘,收件人=‘630571017@qq.com‘,邮件内容=‘邮件内容‘)
mail(主题=‘我是主题‘,)

#函数定义
def mylen(s1):
    """计算s1的长度"""
    length = 0
    for i in s1:
        length = length+1
    return length

#函数调用
str_len = mylen("hello world")
print(‘str_len : %s‘%str_len)

带参数的函数

class file(object)
    def close(self): # real signature unknown; restored from __doc__
        关闭文件
        """
        close() -> None or (perhaps) an integer.  Close the file.
         
        Sets data attribute .closed to True.  A closed file cannot be used for
        further I/O operations.  close() may be called more than once without
        error.  Some kinds of file objects (for example, opened by popen())
        may return an exit status upon closing.
        """
 
    def fileno(self): # real signature unknown; restored from __doc__
        文件描述符  
         """
        fileno() -> integer "file descriptor".
         
        This is needed for lower-level file interfaces, such os.read().
        """
        return 0    
 
    def flush(self): # real signature unknown; restored from __doc__
        刷新文件内部缓冲区
        """ flush() -> None.  Flush the internal I/O buffer. """
        pass
 
 
    def isatty(self): # real signature unknown; restored from __doc__
        判断文件是否是同意tty设备
        """ isatty() -> true or false.  True if the file is connected to a tty device. """
        return False
 
 
    def next(self): # real signature unknown; restored from __doc__
        获取下一行数据，不存在，则报错
        """ x.next() -> the next value, or raise StopIteration """
        pass
 
    def read(self, size=None): # real signature unknown; restored from __doc__
        读取指定字节数据
        """
        read([size]) -> read at most size bytes, returned as a string.
         
        If the size argument is negative or omitted, read until EOF is reached.
        Notice that when in non-blocking mode, less data than what was requested
        may be returned, even if no size parameter was given.
        """
        pass
 
    def readinto(self): # real signature unknown; restored from __doc__
        读取到缓冲区，不要用，将被遗弃
        """ readinto() -> Undocumented.  Don‘t use this; it may go away. """
        pass
 
    def readline(self, size=None): # real signature unknown; restored from __doc__
        仅读取一行数据
        """
        readline([size]) -> next line from the file, as a string.
         
        Retain newline.  A non-negative size argument limits the maximum
        number of bytes to return (an incomplete line may be returned then).
        Return an empty string at EOF.
        """
        pass
 
    def readlines(self, size=None): # real signature unknown; restored from __doc__
        读取所有数据，并根据换行保存值列表
        """
        readlines([size]) -> list of strings, each a line from the file.
         
        Call readline() repeatedly and return a list of the lines so read.
        The optional size argument, if given, is an approximate bound on the
        total number of bytes in the lines returned.
        """
        return []
 
    def seek(self, offset, whence=None): # real signature unknown; restored from __doc__
        指定文件中指针位置
        """
        seek(offset[, whence]) -> None.  Move to new file position.
         
        Argument offset is a byte count.  Optional argument whence defaults to
(offset from start of file, offset should be >= 0); other values are 1
        (move relative to current position, positive or negative), and 2 (move
        relative to end of file, usually negative, although many platforms allow
        seeking beyond the end of a file).  If the file is opened in text mode,
        only offsets returned by tell() are legal.  Use of other offsets causes
        undefined behavior.
        Note that not all file objects are seekable.
        """
        pass
 
    def tell(self): # real signature unknown; restored from __doc__
        获取当前指针位置
        """ tell() -> current file position, an integer (may be a long integer). """
        pass
 
    def truncate(self, size=None): # real signature unknown; restored from __doc__
        截断数据，仅保留指定之前数据
        """
        truncate([size]) -> None.  Truncate the file to at most size bytes.
         
        Size defaults to the current file position, as returned by tell().
        """
        pass
 
    def write(self, p_str): # real signature unknown; restored from __doc__
        写内容
        """
        write(str) -> None.  Write string str to file.
         
        Note that due to buffering, flush() or close() may be needed before
        the file on disk reflects the data written.
        """
        pass
 
    def writelines(self, sequence_of_strings): # real signature unknown; restored from __doc__
        将一个字符串列表写入文件
        """
        writelines(sequence_of_strings) -> None.  Write the strings to the file.
         
        Note that newlines are not added.  The sequence can be any iterable object
        producing strings. This is equivalent to calling write() for each string.
        """
        pass
 
    def xreadlines(self): # real signature unknown; restored from __doc__
        可用于逐行读取文件，非全部
        """
        xreadlines() -> returns self.
         
        For backward compatibility. File objects now include the performance
        optimizations previously implemented in the xreadlines module.
        """
        pass

class TextIOWrapper(_TextIOBase):
    """
    Character and line based layer over a BufferedIOBase object, buffer.
    
    encoding gives the name of the encoding that the stream will be
    decoded or encoded with. It defaults to locale.getpreferredencoding(False).
    
    errors determines the strictness of encoding and decoding (see
    help(codecs.Codec) or the documentation for codecs.register) and
    defaults to "strict".
    
    newline controls how line endings are handled. It can be None, ‘‘,
    ‘\n‘, ‘\r‘, and ‘\r\n‘.  It works as follows:
    
    * On input, 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 newline 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.
    
    * On output, 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.
    
    If line_buffering is True, a call to flush is implied when a call to
    write contains a newline character.
    """
    def close(self, *args, **kwargs): # real signature unknown
        关闭文件
        pass

    def fileno(self, *args, **kwargs): # real signature unknown
        文件描述符  
        pass

    def flush(self, *args, **kwargs): # real signature unknown
        刷新文件内部缓冲区
        pass

    def isatty(self, *args, **kwargs): # real signature unknown
        判断文件是否是同意tty设备
        pass

    def read(self, *args, **kwargs): # real signature unknown
        读取指定字节数据
        pass

    def readable(self, *args, **kwargs): # real signature unknown
        是否可读
        pass

    def readline(self, *args, **kwargs): # real signature unknown
        仅读取一行数据
        pass

    def seek(self, *args, **kwargs): # real signature unknown
        指定文件中指针位置
        pass

    def seekable(self, *args, **kwargs): # real signature unknown
        指针是否可操作
        pass

    def tell(self, *args, **kwargs): # real signature unknown
        获取指针位置
        pass

    def truncate(self, *args, **kwargs): # real signature unknown
        截断数据，仅保留指定之前数据
        pass

    def writable(self, *args, **kwargs): # real signature unknown
        是否可写
        pass

    def write(self, *args, **kwargs): # real signature unknown
        写内容
        pass

    def __getstate__(self, *args, **kwargs): # real signature unknown
        pass

    def __init__(self, *args, **kwargs): # real signature unknown
        pass

    @staticmethod # known case of __new__
    def __new__(*args, **kwargs): # real signature unknown
        """ Create and return a new object.  See help(type) for accurate signature. """
        pass

    def __next__(self, *args, **kwargs): # real signature unknown
        """ Implement next(self). """
        pass

    def __repr__(self, *args, **kwargs): # real signature unknown
        """ Return repr(self). """
        pass

    buffer = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default

    closed = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default

    encoding = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default

    errors = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default

    line_buffering = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default

    name = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default

    newlines = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default

    _CHUNK_SIZE = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default

    _finalizing = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default