R help - Jun 2012 - get index of current element in vector

(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]

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On Jun 4, 2012, at 4:25 PM, Erdal Karaca wrote:
> (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
Almost:

vm <- v * scalar * seq(v)
>
> Is that possible without using a loop?
>
--

David Winsemius, MD
West Hartford, CT

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]]
>
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