Beginner’s Guide to Python’ Enumerate Function
- 时间:2020-09-18 17:39:21
- 分类:网络文摘
- 阅读:116 次

python
You may see Python code like this:
1 2 | for i,v in enumerate(data): pass |
for i,v in enumerate(data): pass
So, what does the enumerate() function do? The enumerate() in python takes a list as its first parameter, and optionally support the second parameter, which is the start-index. By default, the index starts at zero.
The enumerate() returns an iterator.
1 2 3 4 5 | >>> a = ['a','b','c'] >>> enumerate(a) <enumerate object at 0x7f04d8738048> >>> list(enumerate(a)) [(0, 'a'), (1, 'b'), (2, 'c')] |
>>> a = ['a','b','c'] >>> enumerate(a) <enumerate object at 0x7f04d8738048> >>> list(enumerate(a)) [(0, 'a'), (1, 'b'), (2, 'c')]
The iterator can be converted to list, and we can see that the enumerate() will return an iterator of tuple, where the first element in the tuple is the incrementing index, and second element of the tuple is the corresponding value in the list. You can start the index from one, by passing the optional second parameter. See below:
1 2 | >>> list(enumerate(a, 1)) [(1, 'a'), (2, 'b'), (3, 'c')] |
>>> list(enumerate(a, 1)) [(1, 'a'), (2, 'b'), (3, 'c')]
You can combine the use of the zip() in Python that is also producing the same iterator, see below:
1 2 3 4 | >>> list(zip(range(len(a)), a)) [(0, 'a'), (1, 'b'), (2, 'c')] >>> list(enumerate(a)) [(0, 'a'), (1, 'b'), (2, 'c')] |
>>> list(zip(range(len(a)), a)) [(0, 'a'), (1, 'b'), (2, 'c')] >>> list(enumerate(a)) [(0, 'a'), (1, 'b'), (2, 'c')]
–EOF (The Ultimate Computing & Technology Blog) —
推荐阅读:四则混合运算顺序 整数小数分数四则运算计算法则 小学学过的运算定律 分数四则运算的意义 小数四则运算的意义 整数四则运算的意义和各部分名称 数学中学过的性质和规律 小数分数百分数互相转化方法 美丽的南湖作文 圣诞节的礼物_关于描写礼物的小学生作文300字
- 评论列表
-
- 添加评论