How to stack columns to rows in Python?

Question

For example, the data structrue is like below.

import pandas as pd

source={
'Genotype1':["CV1","CV1","CV1","CV1","CV1"], 
'Grain_weight1':[25,26,30,31,29], 
'Genotype2':["CV2","CV2", "CV2","CV2","CV2"],
'Grain_weight2':[29,32,33,32,30]
}

df=pd.DataFrame(source, index=[1,2,3,4,5])
df

and now I’d like to transpose two columns to rows like below. Could you let me know how to do that?

Thanks,

Asked By: Jin.W.Kim

||

Source

Answer 1

You could do the following:

result = pd.concat(
    [df[["Genotype1", "Grain_weight1"]],
     df[["Genotype2", "Grain_weight2"]].rename(lambda c: f"{c[:-1]}1", axis=1)],
    ignore_index=True
)

Result for the sample:

  Genotype1  Grain_weight1
0       CV1             25
1       CV1             26
2       CV1             30
3       CV1             31
4       CV1             29
5       CV2             29
6       CV2             32
7       CV2             33
8       CV2             32
9       CV2             30

Answered By: Timus

Answer 2

It is not transposing. This is actually vertical stacking. You can achieve the same by the following code:

pd.DataFrame(np.vstack([df[df.columns[2:].to_list()].to_numpy(),
           df[df.columns[:2].to_list()].to_numpy()]), columns = df.columns[:2])

Answered By: SAMIR ORUJOV

How to stack columns to rows in Python?

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