Make Number of Rows Based on Column Values - Pandas/Python

Question

I want to expand my data frame based on numeric values in two columns (index_start and index_end). My df looks like this:

item  index_start  index_end    
A          1            3
B          4            7

I want this to expand to create rows for A from 1 to 3 and rows for B from 4 to 7 like so.

item  index_start  index_end    index
A          1            3         1
A          1            3         2
A          1            3         3
B          4            7         4
B          4            7         5
B          4            7         6
B          4            7         7

Unsure how to implement this in Python/pandas.

Answer 1

You could use .explode()

df['index'] = df.apply(lambda row: list(range(row['index_start'], row['index_end']+1)), axis=1)
df.explode('index')

  item  index_start  index_end index
0    A            1          3     1
0    A            1          3     2
0    A            1          3     3
1    B            4          7     4
1    B            4          7     5
1    B            4          7     6
1    B            4          7     7