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

[Florent D.]

I used within and vapply:

x <- data.frame(Col1 = c("abc/def", "ghi/jkl/mno"), stringsAsFactors = FALSE)
count.slashes <- function(string)sum(unlist(strsplit(string, NULL)) ==
"/")within(x, Col2 <- vapply(Col1, count.slashes, 1))
         Col1 Col21     abc/def    12 ghi/jkl/mno    2

On Thu, Dec 1, 2011 at 1:05 PM, Bert Gunter <gunter.berton at gene.com> wrote:
> ## 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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> ______________________________________________
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