Re: [R] spliting strings ...

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Thu, 13 Dec 2007 14:04:12 +0000 (GMT)

On Thu, 13 Dec 2007, Monica Pisica wrote:

>
> Hi everyone,
>
> I have a vector of strings, each string made up by different number of
> words.

You need to define 'word' and 'first'. Your solution says the first word of " aa" is "", which is not what most people would think.

> I want to get a new vector which has only the first word of each
> string in the first vector. I came up with this:
>
> str <- c('aaa bbb', 'cc', 'd eee aa', 'mmm o n')
> str1 <- rep(1, length(str))
> for (i in 1:length(str)) {
> str1[i] <- strsplit(str, " ")[[i]][1]
> }
> str1
> 'aaa' 'cc' 'd' 'mmm'
>
> Now, is there any way to do this simpler?

> sapply(strsplit(str, " "), `[`, 1)
[1] "aaa" "cc" "d" "mmm"

or
> sub("([^ ]+).*", "\\1", str)

I don't see how you got your answer: R does not print like that (and never has).

>
> Thanks,
>
> Monica
>
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PLEASE do!

-- 
Brian D. Ripley,                  ripley_at_stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Thu 13 Dec 2007 - 14:13:01 GMT

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