I have the following pandas dataframe:
colA ColB ColC
0 D
1 G
2 A
3 B
4 C
How can I merge it into (*):
colA
0 D
1 G
2 A
3 B
4 C
So far I tried to:
df = pd.DataFrame.merge([df.ColA, df.ColB, df.ColC], how='right')
df
However, it doesn't worked. How can I get (*)?
You can use DataFrame.sum:
df = df.sum(axis=1)
If NaN values you can fillna first:
df = df.fillna('').sum(axis=1)
print (df)
0 D
1 G
2 A
3 B
4 C
dtype: object
Another solution with apply - join:
df = df.apply(''.join, axis=1)
#df = df.apply(lambda x: ''.join(x), axis=1)
print (df)
0 D
1 G
2 A
3 B
4 C
dtype: object
Solution with Series.combine_first, but need NaN values:
print (df)
colA ColB ColC
0 NaN D NaN
1 NaN NaN G
2 A NaN NaN
3 NaN B NaN
4 C NaN NaN
df = df.colA.combine_first(df.ColB).combine_first(df.ColC)
print (df)
0 D
1 G
2 A
3 B
4 C
Name: colA, dtype: object
df = df.apply(lambda x: ''.join(x), axis=1)print (pd.show_versions())type(df) ? It is DataFrame or Series ?df = df.str.strip() if Series.df[['colA','colB']].apply(''.join, axis=1)