regexpr examples (just to remember)

Find names ending in "_id" or in "_c" (this would be the same as x like any ('%_id', '%_c') in SQL flavour):

x <- c("vp_id","man_id","min_A_d","min_B_d","count_n",
       "type_c","birth_d","gender_c","age_n","hist_y")

x[grep("_(id)|c$", x)]
[1] "vp_id" "man_id" "type_c" "gender_c"


Get rid of everything but the digits:
x <- c("485.2.362.q", "222-445", "889 99 8")
gsub(pattern="[[:punct:]]|[[:alpha:]]|[[:blank:]]", replacement="", x)

gsub(pattern="[^0-9]", x=x, replacement="")

gsub(pattern="[^[:digit:]]", x=x, replacement="")


Extract uppercase words from the beginning of a string following the idea "delete everything which is not uppercase words":

x <- c("RONALD AYLMER Fisher", "CHARLES Pearson", "John Tukey")
sapply(x, function(x) StrTrim(sub(
       pattern=sub(pattern="^[A-ZÄÜÖ -]+\\b\\W+\\b", repl="", x=x)
       , repl="", x, fixed=TRUE)))


... and the fine link:
http://www.powerbasic.com/support/help/pbcc/regexpr_statement.htm