pandas: How to merge multiple dataframes with same column names on one column?

Question

I have N dataframes:

df1:
time  data
1.0   a1
2.0   b1
3.0   c1


df2:
time  data
1.0   a2
2.0   b2
3.0   c2



df3:
time  data
1.0   a3
2.0   b3
3.0   c3

I want to merge all of them on id, thus getting

time  data1    data2    data3
1.0   a1       a2       a3
2.0   b1       b2       b3
3.0   c1       c2       c3

I can assure all the ids are the same in all dataframes.

How can I do this in pandas?

Answer 1

One idea is use concat for list of DataFrame s - only necessary create index by id for each DaatFrame . Also for avoid duplicated columns names is added keys parameter, but it create MultiIndex in output. So added map with format for flatten it:

dfs = [df1, df2, df3]
dfs = [x.set_index('id') for x in dfs]

df = pd.concat(dfs, axis=1, keys=range(1, len(dfs) + 1))
df.columns = df.columns.map('{0[1]}{0[0]}'.format)
df = df.reset_index()
print (df)
   id data1 data2 data3
0   1    a1    a2    a3
1   2    b1    b2    b3
2   3    c1    c2    c3