Python 如何使用熊猫将多行合并为一行

How to combine multiple rows into a single row with pandas

提问by Sandeep Raikar

I need to combine multiple rows into a single row, that would be simple concat with space

我需要将多行合并为一行，这将是简单的空间连接

    View of my dataframe:
  tempx        value
0  picture1         1.5
1  picture555       1.5
2  picture255       1.5
3  picture365       1.5
4  picture112       1.5

I want the dataframe to be converted like this: (space separated) tempx values

我希望像这样转换数据帧：（空格分隔）tempx 值

  Expected output:
  tempx                                                       value
  0     picture1 picture555 picture255 picture365 picture112  1.5

  or
  as a python dict
  {1.5:{picture1 picture555 picture255 picture365 picture112}}

What I have tried :

我尝试过的：

 df_test['tempx']=df_test['tempx'].str.cat(sep=' ')

this works but it combines the rows in all the columns like this:

这有效，但它组合了所有列中的行，如下所示：

      tempx        value
0  picture1 picture555 picture255 picture365 picture112 1.5
1  picture1 picture555 picture255 picture365 picture112 1.5
2  picture1 picture555 picture255 picture365 picture112 1.5
3  picture1 picture555 picture255 picture365 picture112 1.5
4  picture1 picture555 picture255 picture365 picture112 1.5

Is there any elegant solution?

有什么优雅的解决方案吗？

回答by jezrael

You can use groupbyand applyfunction join:

您可以使用groupby和apply功能join：

print df.groupby('value')['tempx'].apply(' '.join).reset_index()
   value                                              tempx
0    1.5  picture1 picture555 picture255 picture365 pict...