在Pandas DataFrame中使用比较列表的问题 [英] Issues using compare lists in pandas DataFrame

问题描述

我在pandas中有一个DataFrame，其中一种列类型是int上的列表，像这样:

I have a DataFrame in pandas with one of the column types being a list on int, like so:

df = pandas.DataFrame([[1,2,3,[4,5]],[6,7,8,[9,10]]], columns=['a','b','c','d'])
>>> df
   a  b  c        d
0  1  2  3   [4, 5]
1  6  7  8  [9, 10]

我想使用d建立一个过滤器，但是正常的比较操作似乎不起作用:

I'd like to build a filter using d, but the normal comparison operations don't seem to work:

>>> df['d'] == [4,5]
0    False
1    False
Name: d, dtype: bool

但是当我逐行检查时，我得到了期望的结果

However when I inspect row by row, I get what I would expect

>>> df.loc[0,'d'] == [4,5]
True

这是怎么回事?如何进行列表比较?

What's going on here? How can I do list comparisons?

推荐答案

这是一个奇怪的问题，它可能与列表不可散列有关 我会申请:

It is a curious issue, it probably has to do with the fact that list are not hashable I would go for apply:

df['d'].apply(lambda x: x == [4,5])

当然，如DSM所建议的，以下工作可以实现:

Of course as suggested by DSM, the following works:

df = pd.DataFrame([[1,2,3,(4,5)],[6,7,8,(9,10)]], columns=['a','b','c','d'])
df['d'] == (4,5)

另一种解决方案是使用list comprehension:

Another solution is use list comprehension:

df[[x == [4, 5] for v in df['col2']]]

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