How to count overlap rows among multiple dataframes?

问题

I have a multiple dataframe like below.

df1 = pd.DataFrame({'Col1':["aaa","ddd","ggg"],'Col2':["bbb","eee","hhh"],'Col3':"ccc","fff","iii"]})
df2= pd.DataFrame({'Col1':["aaa","zzz","qqq"],'Col2':["bbb","xxx","eee"],'Col3':["ccc", yyy","www"]})
df3= pd.DataFrame({'Col1':"rrr","zzz","qqq","ppp"],'Col2':"ttt","xxx","eee","ttt"],'Col3':"yyy","yyy","www","qqq"]})

The dataframe has 3 columns and sometimes their rows overlap among the dataframes. (e.g. df1 and df2 has an identical row as "aaa, bbb, ccc").

I want to know how the rows overlap among dataframes and want to make an output like below.

In this output, if an identical row is detected in the dataframe, the output will be 1, otherwise 0. Does anyone know how to make this output?

In the actual data, I have ~100 dataframes. I first tried to use pd.merge but could not apply this to 100 dataframes...

Thank you very much for your help.

回答1:

Here is one way using concat and get_dummies:

l = [df1,df2,df3] #create a list of dataframes
final = pd.concat([i.assign(key=f"df{e+1}") for e,i in enumerate(l)],sort=False)

final = (final.assign(**pd.get_dummies(final.pop('key')))
        .groupby(['Col1','Col2','Col3']).max().reset_index())

  Col1 Col2 Col3  df1  df2  df3
0  aaa  bbb  ccc    1    1    0
1  ddd  eee  fff    1    0    0
2  ggg  hhh  iii    1    0    0
3  ppp  ttt  qqq    0    0    1
4  qqq  eee  www    0    1    1
5  rrr  ttt  yyy    0    0    1
6  zzz  xxx  yyy    0    1    1

回答2:

Using pandas.concat and groupby:

dfs = [df1,df2,df3]
dfs = [d.assign(df='df%s' % n) for n, d in enumerate(dfs, start=1)]
new_df = pd.concat(dfs).groupby(['Col1', 'Col2', 'Col3','df']).size().unstack(fill_value=0)
print(new_df)

Output:

df              df1  df2  df3
Col1 Col2 Col3               
aaa  bbb  ccc     1    1    0
ddd  eee  fff     1    0    0
ggg  hhh  iii     1    0    0
ppp  ttt  qqq     0    0    1
qqq  eee  www     0    1    1
rrr  ttt  yyy     0    0    1
zzz  xxx  yyy     0    1    1

回答3:

Setup:

df1 = pd.DataFrame({'Col1':["aaa","ddd","ggg"],'Col2':["bbb","eee","hhh"],'Col3':["ccc","fff","iii"]})
df2= pd.DataFrame({'Col1':["aaa","zzz","qqq"],'Col2':["bbb","xxx","eee"],'Col3':["ccc", "yyy","www"]})
df3= pd.DataFrame({'Col1':["rrr","zzz","qqq","ppp"],'Col2':["ttt","xxx","eee","ttt"],'Col3':["yyy","yyy","www","qqq"]})

Solution:

First create a indicate column for each dataframe, then concat, groupby and sum.

df1['df1'] = df2['df2'] = df3['df3'] = 1
(
    pd.concat([df1, df2, df3], sort=False)
    .groupby(by=['Col1', 'Col2', 'Col3'])
    .max().astype(int)
    .reset_index()
)

        Col1    Col2    Col3    df1 df2 df3
0       aaa     bbb     ccc     1   1   0
1       ddd     eee     fff     1   0   0
2       ggg     hhh     iii     1   0   0
3       ppp     ttt     qqq     0   0   1
4       qqq     eee     www     0   1   1
5       rrr     ttt     yyy     0   0   1
6       zzz     xxx     yyy     0   1   1

来源：https://stackoverflow.com/questions/59853457/how-to-count-overlap-rows-among-multiple-dataframes

标签

python

pandas

merge

overlap