如何在Pandas的数据框中将列合并为单一列?

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英文:

How to merge columns into single column in dataframe pandas?

问题

import pandas as pd

# Original dataframe
data_1 = [['Jack', 'Everdeen', 10000, 20000],
          ['Rita', 'Lawrence', 4000, 2000],
          ['Amy', 'Donnie', 5000, 9000]]

df_1 = pd.DataFrame(data_1, columns=['Parent', 'Family Name', 'Money A', 'Money B'], dtype=float)

# Melt the dataframe to achieve the desired format
melted_df = pd.melt(df_1, id_vars=['Parent', 'Family Name'], var_name='Money', value_name='Amount')

# Sort the melted dataframe by 'Parent' and 'Family Name'
sorted_df = melted_df.sort_values(by=['Parent', 'Family Name'])

print(sorted_df)

Output:

  Parent Family Name    Money  Amount
0   Jack    Everdeen  Money A  10000.0
3   Jack    Everdeen  Money B  20000.0
1   Rita    Lawrence  Money A   4000.0
4   Rita    Lawrence  Money B   2000.0
2    Amy      Donnie  Money A   5000.0
5    Amy      Donnie  Money B   9000.0

This code will give you the desired output by melting the original dataframe and sorting it accordingly.

英文:

Original dataframe

Parent  Family Name  Money A  Money B

Jack    Everdeen     10000    20000
Rita    Lawrence     4000     2000
Amy     Donnie       5000     9000

What I want.

Parent  Family Name  Money     Money

Jack    Everdeen     Money A   10000    
Jack    Everdeen     Money B   20000
Rita    Lawrence     Money A   4000     
Rita    Lawrence     Money B   2000
Amy     Donnie       Money A   5000     
Amy     Donnie       Money B   9000

I tried it with pivot function but it does not work. My code is as follows.

data_1 = [['Jack','Everdeen',10000,20000],['Rita','Lawrence',4000,2000],['Amy','Donnie',5000,9000]]
df_1 = pd.DataFrame(data_1,columns=['Parent','Family Name','Money A','Money B'],dtype=float)
print(df_1)
loading_pivot_table = pd.pivot_table(df_1
                                     ,index = ['Parent','Family Name']
                                     ,columns = ['Parent','Family Name']
                             ,values = ['Money A','Money B']
                            ,fill_value = 0)
#convert pivot table to DataFrame
loading_pivot_table_convert = loading_pivot_table.reset_index()
print(loading_pivot_table_convert)

答案1

得分: 1

pd.melt(df_1, id_vars=['Parent','Family Name'], var_name='MoneyCol', value_name='Money').sort_values('Parent',ascending=False)
英文:

Melt it

 pd.melt(df_1, id_vars=['Parent','Family Name'], var_name='MoneyCol', value_name='Money').sort_values('Parent',ascending=False)
Out[13]: 
  Parent Family Name MoneyCol    Money
1   Rita    Lawrence  Money A   4000.0
4   Rita    Lawrence  Money B   2000.0
0   Jack    Everdeen  Money A  10000.0
3   Jack    Everdeen  Money B  20000.0
2    Amy      Donnie  Money A   5000.0
5    Amy      Donnie  Money B   9000.0

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  • 本文由 发表于 2023年1月6日 14:12:06
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