Question

如何从具有两列（auth1和auth2）的列表的共同作者列表中生成数据框每对夫妇一行？

coauthors = []
coauthors.append((("f","g"),("f","h"),("g","h"))) # combinations of f,g,h
coauthors.append((("i","j"),("i","k"),("i","l"),("j","k"),("j","l"),("l","k"))) # combinations of i,j,k,l
coauthors.append((("a","b"))) # combinations of a,b
for s in coauthors:
   print(*s)

侧面问题：为什么上面打印的最后一行不是（'a'，'b'），而是（b）？

Answer 1

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extend

这具有通过传递的iterable元素扩展原始列表的作用，而不是将传递的iterable作为原始列表的单个新元素附加。

还要注意，我在上面的最后一行中添加了一个逗号（以解决您的副问题中的问题）。这是为了告诉Python，您希望将一个元组的元组传递给append（外部元组仅包含一个元组）。如果没有这个逗号，则忽略外括号，Python认为您仅通过元组coauthors = [] coauthors.extend((("f","g"),("f","h"),("g","h"))) # combinations of f,g,h coauthors.extend((("i","j"),("i","k"),("i","l"),("j","k"),("j","l"),("l","k"))) # combinations of i,j,k,l coauthors.extend((("a","b"),)) # combinations of a,b。

这给出了长度为2的10个元组的列表，而不是使用extend生成的嵌套结构。从这里开始，创建DataFrame很容易：

('a', 'b')

给予：

append

Answer 2

很难告诉您是否具有这些值，或对组合进行硬编码。但是，如果使用itertools，则可以轻松得多。创建一个列表列表，每个子列表都是您要从中创建配对的作者的分组，然后使用链和组合将所有配对放入DataFrame

import pandas as pd
from itertools import combinations, chain
groups = [['f', 'g', 'h'], ['i', 'j', 'k', 'l'], ['a', 'b']]

pd.DataFrame(chain.from_iterable([combinations(x, 2) for x in groups]),
             columns=['auth1', 'auth2'])

输出：

  auth1 auth2
0     f     g
1     f     h
2     g     h
3     i     j
4     i     k
5     i     l
6     j     k
7     j     l
8     k     l
9     a     b

如果还需要为每个组添加唯一的ID，则可以合并一堆较小的DataFrames：

pd.concat([
    pd.DataFrame(data, columns=['auth1', 'auth2']).assign(id=gid) 
        for data,gid in zip([combinations(x, 2) for x in groups], range(len(groups)))
], ignore_index=True)

  auth1 auth2  id
0     f     g   0
1     f     h   0
2     g     h   0
3     i     j   1
4     i     k   1
5     i     l   1
6     j     k   1
7     j     l   1
8     k     l   1
9     a     b   2

或者，您可以将内容解包到3个元素列表的列表中，并调用pd.DataFrame一次：

pd.DataFrame([[*z, gid] for data,gid in zip([combinations(x, 2) for x in groups], range(len(groups))) for z in data],
              columns=['auth1', 'auth2', 'id'])

如何将可变数量的“夫妇”列表转换为两列数据框？

2 个答案:

输出：