返回 pandas 数据框中特定值的列名 [英] Return the column name(s) for a specific value in a pandas dataframe

问题描述

我在其他语言(例如R或SQL)中找到了此选项，但是我不太确定如何在Pandas中进行此操作.

where I have found this option in other languages such as R or SQL but I am not quite sure how to go about this in Pandas.

因此，我有一个包含1262列和1行的文件，并且每次出现特定值时都需要返回列标题.

So I have a file with 1262 columns and 1 row and need the column headers to return for every time that a specific value appears.

比如说这个测试数据框:

Say for example this test dataframe:

Date               col1    col2    col3    col4    col5    col6    col7 
01/01/2016 00:00   37.04   36.57   35.77   37.56   36.79   35.90   38.15 

我需要找到列名称，例如其中值= 38.15.最好的方法是什么?

And I need to locate the column name for e.g. where value = 38.15. What is the best way of doing so?

谢谢

推荐答案

由于您只有一行，因此您可以对结果调用iloc[0]并使用它来屏蔽列:

Seeing as you only have a single row then you can call iloc[0] on the result and use this to mask the columns:

In [47]:
df.columns[(df == 38.15).iloc[0]]

Out[47]:
Index(['col7'], dtype='object')

打破以上规定:

In [48]:
df == 38.15

Out[48]:
             Date   col1   col2   col3   col4   col5   col6  col7
01/01/2016  False  False  False  False  False  False  False  True

In [49]:
(df == 38.15).iloc[0]

Out[49]:
Date    False
col1    False
col2    False
col3    False
col4    False
col5    False
col6    False
col7     True
Name: 01/01/2016, dtype: bool

您还可以使用 idxmax axis=1的a>:

You can also use idxmax with param axis=1:

In [52]:
(df == 38.15).idxmax(axis=1)[0]

Out[52]:
'col7'

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