将多个熊猫数据框组合成一个多索引数据框

Question

I have three dataframes with equivalent indices, index names and column names:

DF1:
         value
index
    0       a0
    1       a1
    2       a2
    3       a3

DF2:
         value
index
    0       b0
    1       b1
    2       b2
    3       b3

DF3:
         value
index
    0       c0
    1       c1
    2       c2
    3       c3

I'd like to combine all 3 into a single multi-index dataframe, where the old index is now a column, and the new index is now ['DF1', 'DF2', 'DF3'].

             old_index     value
new_index
      DF1            0        a0
                     1        a1
                     2        a2
                     3        a3
      DF2            0        b0
                     1        b1
                     2        b2
                     3        b3
      DF3            0        c0
                     1        c1
                     2        c2
                     3        c3

What's the easiest way to go about this?

Answer 1

IIUC

l=[DF1,DF2,DF3]

pd.concat(l,keys= ['DF1', 'DF2', 'DF3'],axis=0).reset_index(level=1)