You cas use isTRUE:
isTRUE(grep("a", "bbbb") > 0)
On Sat, Jul 4, 2009 at 2:56 PM, Mark Kimpel <mwkim...@gmail.com> wrote:
> I am using grep to locate colnames to automate a report build and have
> run into a problem when a colname is not found. The use of integer(0)
> in a conditional statement seems to be a no no as it has length 0.
> Below is a self-contained trivial example. I would like to get
> something like "NA" or -1 for the position when it is not found OR
> learn a way to use integer(0) or some "cast" of it in a logical
> statement. Example, output, and sessionInfo follow. Thanks, Mark
>
> ####################################3
> vec.1 <- c("a", "b", "c")
> vec.2 <- c("a", "c", "d")
> for (i in 1:length(vec.1)){
> for (j in 1:length(vec.2)){
> print(paste("i:", i, " j:", j, sep = ""))
> pos <- grep(vec.1[i], vec.2[j])
> if (pos > 0){
> print("pos identified")
> }
> else{
> print("pos not found")
> }
> }
> }
> ################################
>
> > #################################3
> > vec.1 <- c("a", "b", "c")
> > vec.2 <- c("a", "c", "d")
> > for (i in 1:length(vec.1)){
> + for (j in 1:length(vec.2)){
> + print(paste("i:", i, " j:", j, sep = ""))
> + pos <- grep(vec.1[i], vec.2[j])
> + if (pos > 0){
> + print("pos identified")
> + }
> + else{
> + print("pos not found")
> + }
> + }
> + }
> [1] "i:1 j:1"
> [1] "pos identified"
> [1] "i:1 j:2"
> Error in if (pos > 0) { : argument is of length zero
> No suitable frames for recover()
> > ###############
> > sessionInfo()
> R version 2.9.1 (2009-06-26)
> x86_64-unknown-linux-gnu
>
> locale:
>
> LC_CTYPE=en_US.UTF-8;LC_NUMERIC=C;LC_TIME=en_US.UTF-8;LC_COLLATE=en_US.UTF-8;LC_MONETARY=C;LC_MESSAGES=en_US.UTF-8;LC_PAPER=en_US.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US.UTF-8;LC_IDENTIFICATION=C
>
> attached base packages:
> [1] tcltk stats graphics grDevices datasets utils methods
> [8] base
>
> other attached packages:
> [1] sfsmisc_1.0-7 KEGG.db_2.2.11 GO.db_2.2.11
> [4] rat2302.db_2.2.11 GOstats_2.10.0 RSQLite_0.7-1
> [7] DBI_0.2-4 graph_1.22.2 Category_2.10.1
> [10] AnnotationDbi_1.6.1 qvalue_1.18.0 limma_2.18.2
> [13] affy_1.22.0 Biobase_2.4.1
>
> loaded via a namespace (and not attached):
> [1] affyio_1.12.0 annotate_1.22.0 genefilter_1.24.2
> [4] GSEABase_1.6.1 preprocessCore_1.6.0 RBGL_1.20.0
> [7] splines_2.9.1 survival_2.35-4 tools_2.9.1
> [10] XML_2.5-3 xtable_1.5-5
> ------------------------------------------------------------
> Mark W. Kimpel MD ** Neuroinformatics ** Dept. of Psychiatry
> Indiana University School of Medicine
>
> 15032 Hunter Court, Westfield, IN 46074
>
> (317) 490-5129 Work, & Mobile & VoiceMail
>
> "The real problem is not whether machines think but whether men do."
> -- B. F. Skinner
>
> ______________________________________________
> 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.
>
--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
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