[R] Double Roop

[David Winsemius]

On Jun 30, 2015, at 6:04 AM, Peter Maclean via R-help wrote:

>  Hi EverybodyI am trying to make an object with  length(a) * length(b) element using a double loop. But I am getting the last part only.  A simple script is
> a <- c("A-AA", "B-BB", "C-CC")
> b    <- seq(1, 5)
> pre <- NULL
> post <- NULL
> page <- NULLfor(j in 1:length(a)) {
>    for(i in 1:length(b)){
>        pre[j]  <- strsplit(a[j],"-")[[1]][1] 
>           post[j] <- strsplit(a[j],"-")[[1]][2] 
>             page[i] <- paste0(pre[j], b[i],post[j])  
> }}Peter Maclean
> Department of Economics
> UDSM
> 	[[alternative HTML version deleted]]

If you don't want folks here to think you have difficulty with the English language in the posting guide or with managing computer applications, you will set your mail-client to plain-text for communications to r-help. Notice that your code was a bit mangled by the HTML format. This is sometimes much more of a problem than it was in this instance. You've been posting since 2011 so really have no excuse for continuing to flout the mailing list norms:

> page <- paste( rep(a, length(b) ), rep(b, each =length(a) ) )
> 
> page
 [1] "A-AA 1" "B-BB 1" "C-CC 1" "A-AA 2" "B-BB 2" "C-CC 2" "A-AA 3"
 [8] "B-BB 3" "C-CC 3" "A-AA 4" "B-BB 4" "C-CC 4" "A-AA 5" "B-BB 5"
[15] "C-CC 5"

> 
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David Winsemius
Alameda, CA, USA