[R] count occurrence and distance of characters in string

[Charles C. Berry]

On Fri, 5 Nov 2010, Immanuel wrote:

> Hey,
>
> thanks for the answer, actually I already typed an example
> but deleted it since I thought it's superfluous.
> regards
>
> ---------
> string <- "kjokllokkoadddo"
>
> # f1(string, "o") should return that "o" was found 4 times
> # f2(string, "o") should return that the distances between the "o"'s
> found is 3 , 2, 4
> ---------

In that case, I'd use split:

> res <- split(seq(nchar(string)),unlist(strsplit(string,'')))
> length(res[['o']])
[1] 4
> ## or 
> sapply(res,length)
a d j k l o
1 3 1 4 2 4
> diff(res[['o']])-1
[1] 3 2 4
> # or
> sapply(sapply(res,diff),"-",1)
$a
numeric(0)

$d
[1] 0 0

$j
numeric(0)

$k
[1] 2 3 0

$l
[1] 0

$o
[1] 3 2 4

>
Chuck


>
>
> On 11/05/2010 12:28 AM, Charles C. Berry wrote:
>> On Thu, 4 Nov 2010, Immanuel wrote:
>>
>>> Hello all,
>>>
>>> I want to know how often one character occurs in a given string
>>> and the distance from between every two occurences. (distance = other
>>> characters between them).
>>
>> You should provide "commented, minimal, self-contained, reproducible
>> code" as asked.
>>
>> And especially for a question like this one with many simple answers
>> that RespondeRs will shower you with if only you give them a starting
>> point.
>>
>> Use tapply, strsplit, seq, nchar, unlist, diff, "-", and table for one
>> way.
>>
>> Chuck
>>
>>>
>>> thanks
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>> Charles C. Berry                            Dept of Family/Preventive
>> Medicine
>> cberry at tajo.ucsd.edu                UC San Diego
>> http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego
>> 92093-0901
>>
>>
>>
>
>

Charles C. Berry                            Dept of Family/Preventive Medicine
cberry at tajo.ucsd.edu			    UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901