Thanks Chouser!! I needed it just to test the 'nth'. I had to ask, just couldn't figure it out :-)
Yes, I prefer re-seq - especially with such nice tools like http://cljre.com/ from Mark McGranaghan http://groups.google.com/group/clojure/browse_frm/thread/bbc9fd453667d953/a79a738cbe7f41e9 Frantisek On 22 Ún, 02:37, Chouser <chou...@gmail.com> wrote: > On Sat, Feb 21, 2009 at 1:34 PM, Frantisek Sodomka <fsodo...@gmail.com> wrote: > > > nth claims to also work on regex Matchers: > > > user=> (doc nth) > > ------------------------- > > clojure.core/nth > > ([coll index] [coll index not-found]) > > Returns the value at the index. get returns nil if index out of > > bounds, nth throws an exception unless not-found is supplied. nth > > also works for strings, Java arrays, regex Matchers and Lists, and, > > in O(n) time, for sequences. > > > Please, could somebody show me an example of that? I tried things > > along the lines of: > > > user=> (re-seq #"a" "ababaa") > > ("a" "a" "a" "a") > > user=> (re-matcher #"a" "ababaa") > > #<Matcher java.util.regex.Matcher[pattern=a region=0,6 lastmatch=]> > > user=> (nth (re-matcher #"a" "ababaa") 0) > > java.lang.IllegalStateException: No match found (NO_SOURCE_FILE:0) > > user=> (seq (re-matcher #"a" "ababaa")) > > java.lang.IllegalArgumentException: Don't know how to create ISeq > > from: Matcher (NO_SOURCE_FILE:0) > > > ... but no success so far. > > Valiant attempts, all. But Matcher is a mutable Java object -- you're > trying to use nth on it before it's been fully initialized. Calling > it's find method (or using the single-arg form of re-find) will cause > it to refer to the first match in the string, at which point nth can > be used to pick out the group you want: > > user=> (def m (re-matcher #"(a)(b)" "ababaa")) > #'user/m > > user=> (re-find m) > ["ab" "a" "b"] > > user=> (class m) > java.util.regex.Matcher > > user=> (nth m 1) > "a" > > I would recommend avoiding using re-matcher or the single-arg re-find > unless you're sure you need the performance or flexibility in some > particular kind of loop. It's much more pleasant to work with re-seq. > > --Chouser --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
