R/String Manipulation

From QERM Wiki

Here's an example that uses somes string manipulation functions extract some information from a file.

x = readLines("http://wiki.cbr.washington.edu/qerm/index.php/Special:Listusers")
x2 = grep("User:", x, value=T)
starts = as.numeric(gregexpr("/qerm/index.php/User:", x2)[[1]])
ends   = as.numeric(gregexpr("\" title=\"User:",      x2)[[1]])-1
nusers = length(starts)
users = rep(NA,nusers)
userlinks = rep(NA,nusers)
for(i in 1:nusers) userlinks[i] = paste("http://wiki.cbr.washington.edu",substr(x2,starts[i],min(ends[ends>starts[i]])),sep="")
users = sub('http://wiki.cbr.washington.edu/qerm/index.php/User:','',userlinks)
print(cbind(users,userlinks),quote=F)