同时枚举两个 Python 列表？

如何同时枚举两个长度相等的列表？我相信一定有一种更简洁的方式来做到以下几点:

for index, value1 in enumerate(data1):
print index, value1 + data2[index]

我想在 for 循环中使用 index 和 data1[ index ]以及 data2[ index ]。

python
list

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最佳答案

Use zip for both Python2 and Python3:

for index, (value1, value2) in enumerate(zip(data1, data2)):
print(index, value1 + value2)  # for Python 2 use: `print index, value1 + value2` (no braces)

Note that zip runs only up to the shorter of the two lists(not a problem for equal length lists), but, in case of unequal length lists if you want to traverse the whole list then use itertools.izip_longest.

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Suppose you want to use zip:

   >>> for x in zip([1,2], [3,4]):
...     print x
...
(1, 3)
(2, 4)

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for i, (x, y) in enumerate(zip(data1, data2)):

In Python 2.x, you might want to use itertools.izip instead of zip, esp. for very long lists.

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Althought this is not very clear what you look for,

>>> data1 = [3,4,5,7]
>>> data2 = [4,6,8,9]
>>> for index, value in enumerate(zip(data1, data2)):
print index, value[0]+value[1]




0 7
1 10
2 13
3 16

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from itertools import count


for index, value1, value2 in zip(count(), data1, data2):
print(index, value1, value2)

Source: http://www.saltycrane.com/blog/2008/04/how-to-use-pythons-enumerate-and-zip-to/#c2603

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Since it has been mentioned that the length are equal,

for l in range(0, len(a)):
print a[l], b[l]