[R] Counting the occurences of a charater within a string

Bert Gunter gunter.berton at gene.com
Thu Dec 1 19:05:03 CET 2011


## It's not a data frame -- it's just a vector.

> x
[1] "abc/def"     "ghi/jkl/mno"
> gsub("[^/]","",x)
[1] "/"  "//"
> nchar(gsub("[^/]","",x))
[1] 1 2
>

?gsub
?nchar

-- Bert

On Thu, Dec 1, 2011 at 8:32 AM, Douglas Esneault
<Douglas.Esneault at mecglobal.com> wrote:
> I am new to R but am experienced SAS user and I was hoping to get some help on counting the occurrences of a character within a string at a row level.
>
> My dataframe, x,  is structured as below:
>
> Col1
> abc/def
> ghi/jkl/mno
>
> I found this code on the board but it counts all occurrences of "/" in the dataframe.
>
> chr.pos <- which(unlist(strsplit(x,NULL))=='/')
> chr.count <- length(chr.pos)
> chr.count
> [1] 3
>
> I'd like to append a column, say cnt, that has the count of "/" for each row.
>
> Can anyone point me in the right direction or offer some code to do this?
>
> Thanks in advance for the help.
>
> Doug Esneault
>
>
>
>
>
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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