Thanks a lot, Herve'. This worked!
On 23 July 2017 at 22:19, Hervé Pagès <hpa...@fredhutch.org> wrote:
> Hi,
>
> On 07/23/2017 11:43 AM, Davide Piffer wrote:
>>
>> I have a df with a vector v. For each element of the vector, I want to
>> know whether the i-2nd element is the same as the ith element. For
>> example:
>> given
>> v=c(A,C,D,C) the result should be:
>> FALSE,FALSE,FALSE,TRUE.
>>
>> I attempted something using indexing in a for loop such as (bad,
>> incorrect example):
>> for (i in v){
>> if [i]==[i-2] print T
>> else print F
>> }
>>
>> However, this is obviously wrong.
>
>
> Why don't you provide code that is actually valid R code so we
> can run it. Then we can see if it does the right thing or not.
>
>> Can someone provide a nice way to solve this?
>
>
> Does this do what you want?
>
> isSameAsPrevious <- function(v, k=1) c(rep(FALSE, k), head(v,n=-k) ==
> tail(v, n=-k))
>
> Then:
>
>> isSameAsPrevious(v, 2)
> [1] FALSE FALSE FALSE TRUE
>
> H.
>
>
>>
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>> PLEASE do read the posting guide
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.R-2Dproject.org_posting-2Dguide.html&d=DwICAg&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=YfPp2NbGMLV4frEpzG4QQFssqMnld91RlQHDdWcvFtw&s=HGLgncA6cBilW_DkIzjBEizqo1AmvlshmOHQr4td1vc&e=
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> --
> Hervé Pagès
>
> Program in Computational Biology
> Division of Public Health Sciences
> Fred Hutchinson Cancer Research Center
> 1100 Fairview Ave. N, M1-B514
> P.O. Box 19024
> Seattle, WA 98109-1024
>
> E-mail: hpa...@fredhutch.org
> Phone: (206) 667-5791
> Fax: (206) 667-1319
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