Re: [R] string-to-number

From: Marc Schwartz <MSchwartz_at_mn.rr.com>
Date: Sat 19 Aug 2006 - 22:11:25 EST

On Sat, 2006-08-19 at 07:58 -0400, Charles Annis, P.E. wrote:
> Greetings, Amigos:
>
> I have been trying without success to convert a character string,
> > repeated.measures.columns
> [1] "3,6,10"
>
> into c(3,6,10) for subsequent use.
>
> as.numeric(repeated.measures.columns) doesn't work (likely because of the
> commas)
> [1] NA
> Warning message:
> NAs introduced by coercion
>
> I've tried many things including
> strsplit(repeated.measures.columns, split = ",")
>
> which produces a list with only one element, viz:
> [[1]]
> [1] "3" "6" "10"
>
> as.numeric() doesn't like that either.
>
> Clearly: 1) I cannot be the first person to attempt this, and 2) I've made
> this WAY harder than it is.
>
> Would some kind soul please instruct me (and perhaps subsequent searchers)
> how to convert the elements of a string into numbers?
>
> Thank you.

One more step:

> as.numeric(unlist(strsplit(repeated.measures.columns, ",")))
[1] 3 6 10

Use unlist() to take the output of strsplit() and convert it to a vector, before coercing to numeric.

HTH, Marc Schwartz



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