Hello, I am new to R and trying to understand how data manipulation works. I have a CSV file which allows me to build a data table that looks like the following (simplified example):
>db names ages grade_spring_quarter grade_summer_quarter 1: John 24 A A+ 2: Steve 16 B+ B 3: Peter 12 C B+ Now, my goal is to denormalize the data table in order to transform the last 2 columns in rows, therefore obtaining the following: > db2 names ages quarter grades 1: John 24 spring A 2: Steve 16 spring B+ 3: Peter 12 spring C 4: John 24 summer A+ 5: Steve 16 summer B 6: Peter 12 summer B+ I think that I would be able to do it using for loops, but I doubt that's the most efficient way. I have started looking into the Join functionality of data table but so far didn't manage to build db2 from db that way. Do you see how I could proceed? Many thanks Stefano
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