[R] How to test if something doesn't exist

[arun]

Hi Joe,
Not sure about your expected result
 blah<- paste0("x",1:5)
 which(blah=="xyz")
#integer(0)
blah=="xyz"
#[1] FALSE FALSE FALSE FALSE FALSE
 any(blah=="xyz")
#[1] FALSE


 sum(blah=="xyz")
#[1] 0
sum(blah=="x1")
#[1] 1
A.K.



----- Original Message -----
From: Joseph Trubisz <jtrubisz at me.com>
To: r-help at r-project.org
Cc: 
Sent: Wednesday, May 22, 2013 2:08 PM
Subject: [R] How to test if something doesn't exist

Couldn't exactly explain the subject, so here's  the example:

idx<-which(blah[,1]=="xyz")
idx
integer(0)

How do I test that idx has a valid value (namely, > 0)?

TiA,
Joe

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