[R] list substring

calpeda mauro.biasolo at calpeda.it
Thu Apr 2 08:04:02 CEST 2009


I was suggested to use

x = data.frame(string = c( "xxxxx1", "xxxxx2", "yyyyx3"))
 x

 apply(x,1,substr,1,4) 

and it's worked good!
Thank you all


Wacek Kusnierczyk wrote:
> 
> calpeda wrote:
>> thank you,
>> but I m importing data from a txt file and I have a matrix of n*1
>> The function str seems to work only from 1*n
>>
>>   
> 
> you see, it would help if you provided more details from the start.  you
> may still need to do it;  it seems that both solutions you were given
> (mine and the substr one) work for both n*1 and 1*n matrices:
> 
>     # 5*1
>     (strings = matrix(as.character(sample(10^6, 5)), ncol=1))
>    
>     substr(strings, 1, 4)
>     substr(t(strings), 1, 4)
> 
> with a fixed pattern of four digits from the beginning of the string,
> the substr solution is better -- simpler and a few times faster.
> 
> vQ
> 
> ______________________________________________
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 

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