经常逛GitHub的可能关注一个牛叉的项目，叫 What the f*ck Python!
这个项目列出了几乎所有python中那些鲜为人知的功能特性，有些功能第一次遇见时，你会冒出 what the f**k 的感叹。
因为这些例子看起来反人类直觉。
但是如果你理解了它背后的真正原理，你又会惊叹what the f**k， 竟然还有这么骚的操作。
来看看几个例子吧。
微妙的字符串
>>> a = "wtf" >>> b = "wtf" >>> a is b True >>> a = "wtf!" >>> b = "wtf!" >>> a is b False >>> a, b = "wtf!", "wtf!" >>> a is b True # 3.7 版本返回结果为 False.
出乎意料的"is"
>>> a = 256 >>> b = 256 >>> a is b True >>> a = 257 >>> b = 257 >>> a is b False >>> a = 257; b = 257 >>> a is b True
说好的元组不可变呢
some_tuple = ("A", "tuple", "with", "values") another_tuple = ([1, 2], [3, 4], [5, 6]) >>> some_tuple[2] = "change this" TypeError: 'tuple' object does not support item assignment >>> another_tuple[2].append(1000) # 这里不出现错误 >>> another_tuple ([1, 2], [3, 4], [5, 6, 1000]) >>> another_tuple[2] += [99, 999] TypeError: 'tuple' object does not support item assignment >>> another_tuple ([1, 2], [3, 4], [5, 6, 1000, 99, 999])
消失的全局变量
e = 7 try: raise Exception() except Exception as e: pass
输出
>>> print(e) NameError: name 'e' is not defined
到底返回哪个值
def some_func(): try: return 'from_try' finally: return 'from_finally'
输出
>>> some_func() 'from_finally'
诸如此类的例子一共有50多个
如果你能把这50多个特性背后的原理机制全部了解清楚，我相信你的python功力一定会上升一个层次。
