enumerate()

enumerate()
enumerate() 函数用于将一个可遍历的数据对象(如列表、元组或字符串)组合为一个索引序列，同时列出数据和数据下标，一般用在 for 循环当中。

以下是 enumerate() 方法的语法:

enumerate(sequence, [start=0])
示例

>>>seasons = ['Spring', 'Summer', 'Fall', 'Winter']

>>>list(enumerate(seasons))

[(0, 'Spring'), (1, 'Summer'), (2, 'Fall'), (3, 'Winter')]

>>>list(enumerate(seasons, start=1)) # 小标从 1 开始

[(1, 'Spring'), (2, 'Summer'), (3, 'Fall'), (4, 'Winter')]

示例

>>>i = 0
>>>seq = ['one', 'two', 'three']
>>>for element in seq:
...    print(i, seq[i])
...    i += 1
... 
0 one
1 two
2 three



>>>seq = ['one', 'two', 'three']
>>>for i, element in enumerate(seq):
...    print(i, seq[i])
... 
0 one
1 two
2 three
>>>

示例

for i in enumerate(list):
    print(i)

for index,i in enumerate(list):
    print(index,i)