[R] get index of current element in vector

[jim holtman]

Do we need an "Obfuscated R" contest?

On Tue, Jun 5, 2012 at 8:17 AM, Uwe Ligges
<ligges at statistik.tu-dortmund.de> wrote:
>
>
> On 05.06.2012 00:36, Erdal Karaca wrote:
>>
>> Thanks all, that worked!
>>
>> Yes, it should be
>> for (i in 1:length(a)) a[i]<- scalar * a[i] * i
>>
>> And now is...
>>
>> a<- a * scalar * seq_along(a)
>>
>> That is almost as cool as the PERL programming language :-)
>
>
>
> Almost?
>
> Uwe Ligges
>
>
>
>
>> 2012/6/4 Rui Barradas<ruipbarradas at sapo.pt>
>>
>>> Hello,
>>>
>>> Just learning the alphabet? If yes, there's a difference between 'v' and
>>> 'a'.
>>>
>>> Now more seriously. Your description and your loop don't do the same.
>>>
>>> Description:
>>> vm<- scalar * v * seq_along(v)
>>>
>>> Loop:
>>> a<- scalar * a
>>>
>>> Also, seq_along is the way to do it, it works even if length(a) == 0.
>>>
>>> Hope this helps,
>>>
>>> Rui Barradas
>>>
>>> Em 04-06-2012 21:25, Erdal Karaca escreveu:
>>>
>>>> (Just learning R)
>>>>
>>>> I have this vector:
>>>>
>>>> v<- c(1:10)
>>>>
>>>> Now, I want to multiply each element of that vector with a scalar value
>>>> multiplied with its index:
>>>>
>>>> vm<- v * scalar * indexOfCurrentElementOf_v
>>>>
>>>> Is that possible without using a loop?
>>>>
>>>> In a loop I would do this:
>>>>
>>>> for (i in 1:length(a)) a[i]<- scalar * a[i]
>>>>
>>>>        [[alternative HTML version deleted]]
>>>>
>>>> ______________________________________________
>>>> 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.
>>>>
>>>
>>
>>        [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> 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.
>
>
> ______________________________________________
> 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
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.