R help - Mar 2009 - trying to get rid of for loop in simple scenario

Hi,

I have a problem in which i am having trouble vectorizing a snippet of 
my code to avoid a for loop.  A basic example of what I'm trying to do 
is below.

#simple example of problem

x = c(1,1,3,3,6,7,8,8,9)

# I create a vector that contains the unique values of x

y = unique(x)

  y = c(1,3,6,7,8,9)

####  Now I want to create a vector, say z, in which has the same length 
of y, but counts how many repetitions occurred for x.

## I want

z = c(2,2,1,1,2,1)


##   The only way I've been able to think about this problem is in terms 
of a for/while loop to generate z.  I'm having trouble thinking on this one.

If someone could help me out, I would greatly appreciate this.

Carlos

Dear Juan Carlos,
> x = c(1,1,3,3,6,7,8,8,9)
> table(x)
x
1 3 6 7 8 9
2 2 1 1 2 1
> z<-table(x)
> z
x
1 3 6 7 8 9
2 2 1 1 2 1
> as.vector(z)
[1] 2 2 1 1 2 1

Take a look at ?table and ?vector for more information.

HTH,

Jorge


On Mon, Mar 2, 2009 at 4:41 PM, Juancarlos Laguardia
<brassman785@gmail.com>wrote:
> Hi,
>
> I have a problem in which i am having trouble vectorizing a snippet of my
> code to avoid a for loop.  A basic example of what I'm trying to do is
> below.
>
> #simple example of problem
>
> x = c(1,1,3,3,6,7,8,8,9)
>
> # I create a vector that contains the unique values of x
>
> y = unique(x)
>
>  y = c(1,3,6,7,8,9)
>
> ####  Now I want to create a vector, say z, in which has the same length of
> y, but counts how many repetitions occurred for x.
>
> ## I want
>
> z = c(2,2,1,1,2,1)
>
>
> ##   The only way I've been able to think about this problem is in
terms of
> a for/while loop to generate z.  I'm having trouble thinking on this
one.
>
> If someone could help me out, I would greatly appreciate this.
>
> Carlos
>
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> and provide commented, minimal, self-contained, reproducible code.
>
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