python2和python3關於列表推導的差異

看下面兩個例子:

python2的環境:列表中的同名變量名被替換了

>>> x = 'my precious'
>>> dummy = [x for x in 'ABC']
>>> dummy
['A', 'B', 'C']
>>> x
'C'

python3:列表中的同名變量名沒有被替換

>>> x = 'ABC'
>>> dummy = [ord(x) for x in x]
>>> x
'ABC'
>>> dummy
[65, 66, 67]

 

總結:在python3環境,對於列表推導、生成器表達式、字典推導、set推導,python3會維護本身的局部變量,局部變量不會影響上下同名的變量;