Merge columns of pandas dataframe

Question

I've following dataframes.

import pandas as pd
from pprint import pprint

df1 = pd.DataFrame(columns=["A", "B"])
df1["A"] = [1, 2]
df1["B"] = ["A", "B"]

df2 = pd.DataFrame(columns=["A", "C"])
df2["A"] = [3, 4]
df2["C"] = ["C", "D"]

df3 = pd.DataFrame(columns=["A", "C"])
df3["A"] = ["E", "F"]
df3["C"] = [0.1, 0.2]

I want to merge all three dataframes into single dataframe. Expected Output:

df

 A B  C  D
 1 A
 2 B
 3    C  
 4    D
   E     0.1
   F     0.2

I tried using merge function . It appends only 2 dataframes and also appends characters to column names, which I don't intend to do.

df = df1.merge(df2, left_on='A', right_on='C')

I'd like to know if there is an alternative way or in build function to do this.

There is a mistake in df3. Should be df3 = pd.DataFrame(columns=["B", "D"]) df3["B"] = ["E", "F"] df3["D"] = [0.1, 0.2] — pythonic833
– pythonic833, Commented Aug 1, 2019 at 14:55
This mistake is present in all dfs. Your strings (the letters) need to be put in parantheses. — Carsten
– Carsten, Commented Aug 1, 2019 at 14:56

tawab_shakeel · Accepted Answer · 2019-08-01 14:56:18Z

1

df = pd.concat([df1,df2,df3],sort=False).fillna('')

answered Aug 1, 2019 at 14:56

tawab_shakeel

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pythonic833 · Accepted Answer · 2019-08-01 14:54:53Z

1

You are looking for pd.concat

pd.concat([df1,df2,df3])
    A   B   C   D
0   1.0 A   NaN NaN
1   2.0 B   NaN NaN
0   3.0 NaN C   NaN
1   4.0 NaN D   NaN
0   NaN E   NaN 0.1
1   NaN F   NaN 0.2

answered Aug 1, 2019 at 14:54

pythonic833

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Quang Hoang · Accepted Answer · 2019-08-01 14:55:09Z

1

Is it

pd.concat((df1,df2,df3), sort=False)

answered Aug 1, 2019 at 14:55

Quang Hoang

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