Python 笔记 3

列表生成式

[对项的操作 for 项 in 可迭代对象]

[char.upper() for char in ['a', 'b', 'c', 'd', 'e']]

列表生成式中使用 if

[对项的操作 for 项 in 可迭代对象 if 对项的判断]

[2 ** i for i in range(1, 11) if i % 2 == 1 ]

列表生成式中嵌套 for

[对项1和(或)项2的操作 for 项1 in 可迭代对象1 for 项2 in 可迭代对象2]

nums = [1, 2, 3]
chars = ['a', 'b', 'c']
[c * n for n in nums for c in chars]

strings = ['aa', 'bb', 'cc']
[char for string in strings for char in string]

字典生成式

{键: 值 for 项 in 可迭代对象}

{char: char.upper() for char in 'abcde'}

集合生成式

{对项的操作 for 项 in 可迭代对象}

{char.lower() for char in 'ABCDABCD'}