Fill the numbers between two columns in Pandas data frame

Question

I have a Pandas dataframe with below columns:

id  start  end
1   101    101
2   102    104
3   108    109

I want to fill the gaps between start and end with additional rows, so the output may look like this:

id  number
1    101
2    102
2    103
2    104
3    108
3    109

Is there anyway to do it in Pandas? Thanks.

Answer 1

Use nested list comprehension with range and flattening for list of tuples, last use DataFrame constructor:

zipped = zip(df['id'], df['start'], df['end'])

df = pd.DataFrame([(i, y) for i, s, e in zipped for y in range(s, e+1)],
                   columns=['id','number'])
print (df)
   id  number
0   1     101
1   2     102
2   2     103
3   2     104
4   3     108
5   3     109

Answer 2

Here is a pure pandas solution but performance-wise, @jaezrael's solution would be better,

df.set_index('id').apply(lambda x: pd.Series(np.arange(x.start, x.end + 1)), axis = 1)\
.stack().astype(int).reset_index()\
.drop('level_1', 1)\
.rename(columns = {0:'Number'})

    id  Number
0   1   101
1   2   102
2   2   103
3   2   104
4   3   108
5   3   109