[R] how to delete a matrix column

[Ted Harding]

On 17-Jun-2012 17:24:21 ÀîºìÍú wrote:
>> a<-c(1,4)
>> a
> [1] 1 4
>> b<-a*5
>> b
> [1] 5 20
> 
> a is a very long vector , how can i get c(1:5,4:20)?
> i do not want to use a loop.
> 
> thanks very much!

Your question is not quite clear, but I think you mean:

  a is a very long vector, and you want a vector with elements

  a[1],a[2],a[3],a[4],a[5],a[4],a[5],a[6],...,a[20]

If that is the case, then a[c(1:5,4:20)] will do it. Example:

a <- (1:100)
a[c(1:5,4:20)]
# [1]  1  2  3  4  5  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20

Does that help?

If not, try to re-formulate the question!
Ted.

-------------------------------------------------
E-Mail: (Ted Harding) <Ted.Harding at wlandres.net>
Date: 17-Jun-2012  Time: 20:58:01
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