George -
I think you're looking for the ifelse function:
X = c(100,125,110,90)
Y = c(200,110,150,200)
Z = c(125,105,130,75)
AA = c(150,140,200,65)
result = ifelse(X < Z & Y > Z,AA - Z,NA)
result
[1] 25 NA 70 NA
result[!is.na(result)]
[1] 25 70
(I'm assuming you said 50 when you meant 70.)
- Phil Spector
Statistical Computing Facility
Department of Statistics
UC Berkeley
spec...@stat.berkeley.edu
On Thu, 16 Sep 2010, George Coyle wrote:
Hello,
I wrote this code which works fine on a single observation:
x<-100
y<-200
z<-125
aa<-150
if(x<z && y>z) {aa-z}
result: 25
I am trying to apply this logic where x,y,z,and aa are arrays but with very
little success. I have tried using loops and whiles but I always get errors
of various types. I have consulted a few manuals but with limited success.
My hopeful outcome would be:
data:
X Y Z AA
1 100 200 125 150
2 125 110 105 140
3 110 150 130 200
4 90 200 75 65
Here row 1 would return 25, row 2 would return nothing since Z<X, row 3
would be 50, row 4 would be nothing since X>Z.
In this case I am trying to return something where I could call the output a
variable "Z" which would become an array based on the logic above where the
members would be: (25, 50)
I tried using this where the variables are arrays:
if(x<z && y>z) {aa-z}
But I get "NULL"
I tried using this where the variables are arrays:
if(x<z && y>z) {aa-z} else "NA"
But I get "NA"
When I tried using a loop:
for(i in 1:length(x)) if(x<z && y>z) {aa-z} else "NA"
I got "NULL"
An attempt at a "while" statement crashed.
The time series resource (
http://cran.r-project.org/doc/contrib/Ricci-refcard-ts.pdf) is way too
involved. Most online sources I am finding are not good for "if" contingent
array manipulation. Annoyingly, just saying aa-z will work across the
entire array but for some reason my ifs fail. I know the R help group only
wants serious emails so hopefully this will indicate I gave it a
reasonable shot.
Please help
Thanks
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
