迭代 Python 中多个列表中的所有值组合
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Iterate over all combinations of values in multiple lists in Python
提问by DurgaDatta
Given multiple list of possibly varying length, I want to iterate over all combinations of values, one item from each list. For example:
给定多个长度可能不同的列表，我想迭代所有值组合，每个列表中的一个项目。例如：
first = [1, 5, 8]
second = [0.5, 4]
Then I want the output of to be:
然后我希望的输出是：
combined = [(1, 0.5), (1, 4), (5, 0.5), (5, 4), (8, 0.5), (8, 4)]
I want to iterate over the combinedlist. How do I get this done?
我想遍历组合列表。我如何完成这项工作？
采纳答案by Volatility
itertools.productshould do the trick.
itertools.product应该做的伎俩。
>>> import itertools
>>> list(itertools.product([1, 5, 8], [0.5, 4]))
[(1, 0.5), (1, 4), (5, 0.5), (5, 4), (8, 0.5), (8, 4)]
Note that itertools.productreturns an iterator, so you don't need to convert it into a list if you are only going to iterate over it once.
请注意，itertools.product返回一个迭代器，因此如果您只打算对其进行一次迭代，则无需将其转换为列表。
eg.
例如。
for x in itertools.product([1, 5, 8], [0.5, 4]):
# do stuff
回答by spinup
This can be achieved without any imports using a list comprehension. Using your example:
这可以在没有任何导入的情况下使用列表理解来实现。使用您的示例：
first = [1, 5, 8]
second = [0.5, 4]
combined = [(f,s) for f in first for s in second]
print(combined)
# [(1, 0.5), (1, 4), (5, 0.5), (5, 4), (8, 0.5), (8, 4)]
