标签：参数 驼峰命名 块代码 例子 series john def nbsp argument
编码风格
使用 4 空格缩进，而非 TAB
在小缩进（可以嵌套更深）和大缩进（更易读）之间，4空格是一个很好的折中。TAB 引发了一些混乱，最好弃用
折行以确保其不会超过 79 个字符
这有助于小显示器用户阅读，也可以让大显示器能并排显示几个代码文件
使用空行分隔函数和类，以及函数中的大块代码
可能的话，注释独占一行
使用文档字符串
把空格放到操作符两边，以及逗号后面，但是括号里侧不加空格：a = f(1, 2) + g(3, 4)
统一函数和类命名
推荐类名用 驼峰命名， 函数和方法名用 小写_和_下划线。总是用 self 作为方法的第一个参数（关于类和方法的知识详见 初识类 ）
不要使用花哨的编码，如果你的代码的目的是要在国际化环境。Python 的默认情况下，UTF-8，甚至普通的 ASCII 总是工作的最好
同样，也不要使用非 ASCII 字符的标识符，除非是不同语种的会阅读或者维护代码。
找素数
for n in range(2, 10): for x in range(2, n): if n % x == 0: print(n, ‘equals‘, x, ‘*‘, n//x) break else: print(n, ‘is a prime number‘) 2 is a prime number 3 is a prime number 4 equals 2 * 2 5 is a prime number 6 equals 2 * 3 7 is a prime number 8 equals 2 * 4 9 equals 3 * 3
找奇偶
for num in range(2, 10): if num % 2 == 0: print(‘Found an even number‘, num) continue print(‘Found a number‘, num) Found an even number 2 Found a number 3 Found an even number 4 Found a number 5 Found an even number 6 Found a number 7 Found an even number 8 Found a number 9
一个能打印斐波那契的函数
>>> def fib(n): """Print a Fibonacci series up to n.""" a, b = 0, 1 while a < n: print(a, end = ‘ ‘) a, b = b, a+b print() >>> fib(500) 0 1 1 2 3 5 8 13 21 34 55 89 144 233 377
带默认参数的函数
>>> def ask_ok(prompt, retries=4, complaint=‘Yes or no,Please!‘): while True: ok = input(prompt) if ok in (‘y‘, ‘ye‘, ‘yes‘): return True if ok in (‘n‘, ‘no‘, ‘nop‘, ‘nope‘): return False retries = retries - 1 if retries < 0: raise OSError(‘uncooperative user‘) print(complaint) >>> ask_ok(‘Do you really want to quit?‘) Do you really want to quit?what? Yes or no,Please! Do you really want to quit?yes True
默认值只被赋值一次，当默认值是可变对象时会有所不同，比如列表、字典或者大多数类的实例。
例如，下面的函数在后续调用过程中会累积（前面）传给它的参数
>>> def f(a, L=[]): L.append(a) return L >>> print(f(1)) [1] >>> print(f(2)) [1, 2] >>> print(f(3)) [1, 2, 3] >>>
关键字函数
>>> def parrot(voltage, state=‘a stiff‘, action=‘voom‘, type=‘Norwegian Blue‘): print("-- This parrot wouldn‘t", action, end=‘ ‘) print("if you put", voltage, "volts through it.") print("-- Lovely plumage, the", type) print("-- It‘s", state, "!") >>> parrot(1000) -- This parrot wouldn‘t voom if you put 1000 volts through it. -- Lovely plumage, the Norwegian Blue -- It‘s a stiff ! >>> parrot(‘a thousand‘, state=‘pushing up the daisies‘) -- This parrot wouldn‘t voom if you put a thousand volts through it. -- Lovely plumage, the Norwegian Blue -- It‘s pushing up the daisies !
元组、字典的作为参数的函数
>>> def cheeseshop(kind, *arguments, **keywords): print("-- Do you have any", kind, "?") print("-- I‘m sorry, we‘re all out of", kind) for arg in arguments: print(arg) print("-" * 40) keys = sorted(keywords.keys()) for kw in keys: print(kw, ":", keywords[kw]) >>> cheeseshop("Limburger", "It‘s very runny, sir.", "It‘s really very, VERY runny, sir.", shopkeeper="Michael Palin", client="John Cleese", sketch="Cheese Shop Sketch") -- Do you have any Limburger ? -- I‘m sorry, we‘re all out of Limburger It‘s very runny, sir. It‘s really very, VERY runny, sir. ---------------------------------------- client : John Cleese shopkeeper : Michael Palin sketch : Cheese Shop Sketch
函数注解
对于参数的注解出现在紧随参数名之后的冒号之后
对于返回值,它们编写于紧跟在参数列表之后的一个 -> 之后.
>>> def func(a:‘spam‘,b:(1,10),c:float)->int:
return a+b+c
>>> func.__annotations__
{‘a‘: ‘spam‘, ‘b‘: (1, 10), ‘c‘: <class ‘float‘>, ‘return‘: <class ‘int‘>}
标签：参数 驼峰命名 块代码 例子 series john def nbsp argument
原文地址：http://www.cnblogs.com/liyonghua/p/7746006.html
