# [R] change values in data frames

poul morteterre at infonie.fr
Sat Jun 28 17:31:31 CEST 2008

```Thanks a lot, it works perfectly .
Bye
Paul

jholtman wrote:
>
> Is this what you want:
>
>> x
>   cola colb
> 1    1    c
> 2    1    i
> 3    1    i
> 4    1    c
> 5    2    i
> 6    2    c
> 7    2    c
> 8    2    i
> 9    2    i
>> # generate run lengths
>> z <- rle(x\$colb)
>> # calculate offset of each starting sequence
>> offsets <- head(cumsum(c(1, z\$lengths)), -1)
>> # now determine where the 'i' is more than 1
>> long <- which(z\$lengths > 1 & z\$values == 'i')
>> # now replace all 'i' with 'I'
>> x\$colb[x\$colb == 'i'] <- 'I'
>> # replace lon runs with 'h'
>> for (i in long){
> +     x\$colb[(offsets[i]+1):(offsets[i] + z\$lengths[i] - 1)] <-
> rep('h', z\$lengths[i] - 1)
> + }
>> x
>   cola colb
> 1    1    c
> 2    1    I
> 3    1    h
> 4    1    c
> 5    2    I
> 6    2    c
> 7    2    c
> 8    2    I
> 9    2    h
>>
>>
>
>
> On Fri, Jun 27, 2008 at 5:17 AM, poul <morteterre at infonie.fr> wrote:
>>
>> Hello every body,
>> I am quite a new user of R so I beg your pardon for this naive question
>> and
>> the lake of syntax with wich I ask it:
>>
>> I have a data frames like this:
>>
>> cola    colb
>> 1       c
>> 1       i
>> 1       i
>> 1       c
>> 2       i
>> 2       c
>> 2       c
>> 2       i
>> 2       i
>> ...
>> 10000
>>
>> I would like ,for each level of cola and for x in colb:
>>
>> -if colb[x]=="i" and colb[x-1] does not exist (first row in dataframes),
>> then replace colb[x] by "l"
>> -if colb[x]=="i" and colb[x-1]=="c" (previous row in data frmes), then
>> replace colb[x] by "l"
>> -if colb[x]=="i" and colb[x-1]=="i" (previous row in data frmes), then
>> replace colb[x] by "h"
>>
>> Thanks in advance
>>
>> Paul
>>
>> --
>> View this message in context:
>> http://www.nabble.com/change-values-in-data-frames-tp18151205p18151205.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> 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.
>>
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem you are trying to solve?
>
> ______________________________________________
> 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.
>
>

--
View this message in context: http://www.nabble.com/change-values-in-data-frames-tp18151205p18171911.html
Sent from the R help mailing list archive at Nabble.com.

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