python中鮮為人知的功能特性有哪些

本篇內(nèi)容主要講解“python中鮮為人知的功能特性有哪些”，感興趣的朋友不妨來看看。本文介紹的方法操作簡(jiǎn)單快捷，實(shí)用性強(qiáng)。下面就讓小編來帶大家學(xué)習(xí)“python中鮮為人知的功能特性有哪些”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 版本返回結(jié)果為 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

說好的元組不可變呢

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) # 這里不出現(xiàn)錯(cuò)誤
>>> 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])

消失的全局變量

e = 7
try:
    raise Exception()
except Exception as e:
    pass

輸出

>>> print(e)
NameError: name 'e' is not defined

try 遇到 finally到底返回哪個(gè)值

def some_func():
    try:
        return 'from_try'
    finally:
        return 'from_finally'

輸出

>>> some_func()
'from_finally'

到此，相信大家對(duì)“python中鮮為人知的功能特性有哪些”有了更深的了解，不妨來實(shí)際操作一番吧！這里是億速云網(wǎng)站，更多相關(guān)內(nèi)容可以進(jìn)入相關(guān)頻道進(jìn)行查詢，關(guān)注我們，繼續(xù)學(xué)習(xí)！