I have a large dataset where each rate is the same for all ages between age_first and age_last. Below is an example of one row of the dataset:   age_first   age_last   rate    15             20         4.16   My goal is to convert this row into many, with one row for each age, like so:   age   rate 15     4.16 16     4.16 17     4.16 18     4.16 19     4.16 20     4.16 ... View more