I have a dataframe which has a series of lengths in it
eg.,
Length
1.2
3.5
3.6
3.6
Some of these lengths are the same
I want to add a column to my dataframe which has the count/frequency of each length - eg.,
Length Count
1.2 1
3.5 1
3.6 2
Just wondering if anyone knows the most efficient way to do this? Thanks