[R] string-to-number

[Peter Dalgaard]

"Charles Annis, P.E." <Charles.Annis at statisticalengineering.com> writes:

> 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?

3) you're almost there, just not realizing it:

> x <- "3,6,10"
> as.numeric(strsplit(x,split = ",")[[1]])
[1]  3  6 10

or for that matter

> scan(textConnection(x), sep=",")
Read 3 items
[1]  3  6 10

although that leaves you with a dangling open connection.

-- 
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