[R] conditional value assignment

Frank Tamborello franklin.tamborello at uth.tmc.edu
Mon Feb 14 10:02:08 CET 2011


Dear R-Help,

I am trying to compute a new variable, let's call it "target cannon orientation (tco)" based conditionally on old variables, "TargetColor," "CannonOriB," and "CannonOriR." For every case in the data set, if TargetColor is "B" then I want tco to equal the value for that case of CannonOirB, else CannonOriR. I've tried writing for loops and functions that I can feed to sapply. I suspect there must be a simple solution but I cannot seem to get either incantation to perform the assignment. What would be a good way to do this?

Example data:
"TargetColor.1.18."	"CannonOriB.1.18."	"CannonOriR.1.18."
"B"	5	3
"R"	5	3


Example assignment of tco
"tco"
5
3

Thanks much!

Frank Tamborello, PhD
W. M. Keck Postdoctoral Fellow
School of Biomedical Informatics	
University of Texas Health Science Center, Houston
https://xfiles.uth.tmc.edu/Users/ftamborello/public/index.html



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