How can we merge four pandas dataframes horizontally base on a particular column in python-CodePudding

How to merge four pandas dataframes horizontally based on a rank column?
I have four dataframes_

dfOne           
co   name   rank
AA   a      1
RF   b      2
GR   c      3
AS   d      4

dfTwo           
co   name   rank
FG   h      1
HT   j      2
RD   r      3
AR   y      4

dfThree     
rank   place
2      dhht
3      hgd
4      rfn
5      vdr

dfFour      
rank   place
1      ghr
2      dvf
3      rdn
4      mki

How can I merge these four dataframes horizontally based on rank column

My expectation is like this_

df                  
place   co   name   rank   name   co    place
dhht    AA   a      1      h      FG    ghr
hgd     RF   b      2      j      HT    dvf
rfn     GR   c      3      r      RD    rdn
-       AS   d      4      y      AR    mki
vdr     -    -      5      -      -     -

CodePudding user response：

You can set rank as index temporarily and concat horizontally:

dfs = [dfOne, dfTwo, dfThree, dfFour]

out = pd.concat([d.set_index('rank') for d in dfs], axis=1).reset_index()

output:

   rank   co name   co name place place
0     1   AA    a   FG    h   NaN   ghr
1     2   RF    b   HT    j  dhht   dvf
2     3   GR    c   RD    r   hgd   rdn
3     4   AS    d   AR    y   rfn   mki
4     5  NaN  NaN  NaN  NaN   vdr   NaN

CodePudding user response：

You can use:

from functools import reduce

df_list = [dfOne, dfTwo, dfThree, dfFour]
df_result = reduce(lambda  left,right: pd.merge(left,right,on='rank', how='outer'), df_list)

I have found this here: Python: pandas merge multiple dataframes