Duplicate row based on value in different column

Question

I have a dataframe of transactions. Each row represents a transaction of two item (think of it like a transaction of 2 event tickets or something). I want to duplicate each

Answer 1

Answer by using repeat

df.loc[df.index.repeat(df.Quantity)]
Out[448]: 
  Price City Quantity
1    20  NYC        2
1    20  NYC        2
2    30  NYC        2
2    30  NYC        2
3     5  NYC        2
3     5  NYC        2
4   300   LA        2
4   300   LA        2
5    30   LA        2
5    30   LA        2
6   100   LA        2
6   100   LA        2