python所有可能的2个列表元素对，并获取该对的索引

发布于 2024-12-17 18:32:22 字数 236 浏览 2 评论 0原文

假设我有两个列表：

a = list(1,2,3)
b = list(4,5,6)

所以我可以有 9 对这些列表成员：

(1,4)
(1,5)
(1,6)

(2,4)
(2,5)
(2,6)

(3,4)
(3,5)
(3,6)

现在，给定上面的两个列表成员，我可以找出该对的索引吗？就像上面的 (1,4) 是第一对。

let's say I have two lists:

a = list(1,2,3)
b = list(4,5,6)

So I can have 9 pairs of these list members:

(1,4)
(1,5)
(1,6)

(2,4)
(2,5)
(2,6)

(3,4)
(3,5)
(3,6)

Now, given two list members like above, can I find out the pair's index?
Like (1,4) from above would be the 1st pair.

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书间行客 2024-12-24 18:32:22

并完成答案并留在示例中：

import itertools  

a = [1, 2, 3]
b = [4, 5, 6]
c = list(itertools.product(a, b))

idx = c.index((1,4))

但这将是从零开始的列表索引，因此 0 而不是 1。

And to complete the answer and stay in the example:

import itertools  

a = [1, 2, 3]
b = [4, 5, 6]
c = list(itertools.product(a, b))

idx = c.index((1,4))

But this will be the zero-based list index, so 0 instead of 1.

一种方法是：

One way to do this:

Find the first element of the pair your are looking for in the first list:
```
p = (1, 4)
i = a.index(p[0])
```
Find the second element of the pair your are looking for in the second list:
```
j = b.index(p[1])
```
Compute the index in the product list:
```
k = i * len(b) + j
```

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