[R] text search in r

[arun]

Hi,

You could also use these:
library(Biostrings)
 gregexpr2("AB",new)
#[[1]]
#[1]  4 10 14

 length(unlist(gregexpr2("AB",new)))
#[1] 3
 length(unlist(gregexpr2("BA",new)))
#[1] 2

matchPattern("AB",new)
 # Views on a 16-letter BString subject
#subject: AAAABBBBBABBBABB
#views:
  #  start end width
#[1]     4   5     2 [AB]
#[2]    10  11     2 [AB]
#[3]    14  15     2 [AB]
 res1<-matchPattern("AB",new)
length(res1)
#[1] 3
 res2<-matchPattern("BA",new)
 length(res2)
#[1] 2
#another string
new1<-c("ABABAAABABAAAABABABBA")
 res2<-matchPattern("BA",new1)
length(res2)
#[1] 7
 length(unlist(gregexpr2("BA",new1)))
#[1] 7


A.K.



----- Original Message -----
From: rnewbie565 <amy.jacobson2 at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Thursday, August 2, 2012 5:27 PM
Subject: [R] text search in r

I am trying to count the number of times that the characters in a string
change
For example-
new=c(AAAABBBBBABBBABB)
I want to find the number of times that B changes to A and the number of
times that A changes to B. I tried the grep command but I only figured out
the positions of when B changes to A when I only need the number of times it
occurs.




--
View this message in context: http://r.789695.n4.nabble.com/text-search-in-r-tp4638961.html
Sent from the R help mailing list archive at Nabble.com.

______________________________________________
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.