Repeat a row based on column values in pandas

Question

I have this df in pandas:

df = { "id" : ["apple", "potato","lemon"],"som" : [4, 2, 7] , "value" : [1, 2, 4]}
df = pd.DataFrame(df)

I would like to repeat each row based on value. Desired output is:

results_df = {"id" : ["apple", "potato", "potato", "lemon", "lemon", "lemon", "lemon"] , "som" : [4, 2, 2, 7, 7, 7, 7]}

results_df = pd.DataFrame(results_df)

How can I do this please?

Answer 1

You can use numpy.repeat and pandas.DataFrame.loc:

import numpy as np
import pandas as pd

d = { "id": ["apple", "potato", "lemon"], "som": [4, 2, 7], "value": [1, 2, 4]}
df = pd.DataFrame(data=d)
results_df = df.loc[np.repeat(df.index.values, df["value"])]
results_df = results_df.drop(columns=["value"]).reset_index(drop=True)
results_df

Output:

index	id	som
0	apple	4
1	potato	2
2	potato	2
3	lemon	7
4	lemon	7
5	lemon	7
6	lemon	7