R help - Dec 2011 - Counting the occurences of a charater within a string

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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## 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
>
>
>
>
>
>
> Privileged/Confidential Information may be contained in this message. If
you
> are not the addressee indicated in this message (or responsible for
delivery
> of the message to such person), you may not copy or deliver this message to
> anyone. In such case, you should destroy this message and kindly notify the
> sender by reply email. Please advise immediately if you or your employer
> does not consent to email for messages of this kind. Opinions, conclusions
> and other information in this message that do not relate to the official
> business of the GroupM companies shall be understood as neither given nor
> endorsed by it. ? GroupM companies are a member of WPP plc. For more
> information on our business ethical standards and Corporate Responsibility
> policies please refer to our website at
> http://www.wpp.com/WPP/About/
>
>
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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Phone: 467-7374
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On Thu, Dec 1, 2011 at 10:32 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.
Here's an easy way from stringr:

library(stringr)
str_count( c("abc/def", "ghi/jkl/mno"), "/")
# [1] 1 2

Hadley

-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/