python列表生成式

1.

>>> list(range(1, 11))
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

2.

>>> [x * x for x in range(1, 11) if x % 2 == 0]
[4, 16, 36, 64, 100]

3.

L = ['Java' , 'C' , 'Swift' , 'Python' , 123]  
print [s.lower() if isinstance(s , str) else s for s in L ]