[R] matching element of a vector to i-2nd element

[Davide Piffer]

No homework. Just a genuine question

On 23 July 2017 at 22:00, Bert Gunter <bgunter.4567 at gmail.com> wrote:
> Homework?? There is a no homework policy on this list.
>
> Cheers,
> Bert
> Bert Gunter
>
> "The trouble with having an open mind is that people keep coming along
> and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>
>
> On Sun, Jul 23, 2017 at 11:43 AM, Davide Piffer <pifferdavide at gmail.com> 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.
>> Can someone provide a nice way to solve this?
>>
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