[R] Select top three values from data frame
Noah Silverman
noah at smartmediacorp.com
Wed Aug 26 10:36:22 CEST 2009
Hi,
I'm trying to find an easy way to do this.
I want to select the top three values of a specific column in a subset
of rows in a data.frame. I'll demonstrate.
A B C
x 2 1
x 4 1
x 3 2
y 1 5
y 2 6
y 3 8
I want the top 3 values of B from the data.frame where A=X and C <2
I could extract all the rows where C<2, then sort by B, then take the
first 3. But that seems like the wrong way around, and it also will get
messy with real data of over 100 columns.
Any suggestions?
More information about the R-help
mailing list