[R] frequence of patterns in a vector

[David Winsemius]

 > x <- c("ABC", "ABC", "ABC", "A02", "ABC", "RCA", "ABC", "ABC")
 > table(x)
x
A02 ABC RCA
   1   6   1

 > table(x)[c("ABC", "A02", "RCA")]
x
ABC A02 RCA
   6   1   1

On May 29, 2009, at 2:15 PM, liujb wrote:

>
> Dear R users,
>
> Suppose I have a vector that consists of characters like ABC, A02,  
> RCA,
> etc., and there are about 700 of possible characters. For example,
> x <- c("ABC", "ABC", "ABC", "A02", "ABC", "RCA", "ABC", "ABC")
>
> I'd like to get a frequency matrix that looks something like this:
> ABC   6
> A02   1
> RCA   1
>
> I have like 1M numbers of vectors like x (that can have different  
> length
> too). How do I do this?
>
> Thank you very much in advance,
>
> Julia
>


David Winsemius, MD
Heritage Laboratories
West Hartford, CT