如何基于熊猫中另一个数据框中的列对数据框进行排序？

Question

Say I have two dataframes, df1 and df2 in the picture above. I want to sort the df1 based on the Col2 of df2.

So the end result of the df1 should look like the third dataframe in the picture, where the Col2 is in the same values, order in df2.

Answer 1

You can use combination of set_index and reindex for this.

Try this code :

df1 = pd.DataFrame({'Col1': ['a','b','c','d','e'], 'Col2': 
['chocolate','chicken','pizza','icecream','cake'] })
Out :
  Col1       Col2
0    a  chocolate
1    b    chicken
2    c      pizza
3    d   icecream
4    e       cake
df2 = pd.DataFrame({'Col1': ['f','g','h','i','j'], 'Col2': ['chicken','cake','icecream','chocolate','pizza'] })
Out :
  Col1       Col2
0    f    chicken
1    g       cake
2    h   icecream
3    i  chocolate
4    j      pizza
df1 = df1.set_index('Col2')
df1 = df1.reindex(index=df2['Col2'])
df1 = df1.reset_index()
Out :
        Col2 Col1
0    chicken    b
1       cake    e
2   icecream    d
3  chocolate    a
4      pizza    c