Here is what people are talking about when they say do it w/o regular expressions:
#lang racket (require srfi/13) (define (ends-in-: s) (define t (string-trim-right s)) (and (> (string-length t) 0) (char=? (string-ref t (- (string-length t) 1)) #\:))) (ends-in-: "abc") (ends-in-: " abc: ") (ends-in-: " ") On Mar 31, 2011, at 7:38 PM, Charles Hixson wrote: > Hi, > I'm trying to determine whether the last non-whitespace character of a string > is a colon, and I haven't been able to figure out the best way of doing this. > In python I'd just trim the string and look at the character before the end, > but while Racket seems to have a string-length function, it doesn't seem to > have anything analogous to trim. So how should it be done? > > The best I've come up with is to explode the string into a list of > characters, and handle it that way, but that's clearly quite wasteful of both > processing and RAM. (Of course, part of it is that the best way I've figured > to proceed from there is to then copy that list to another list checking at > each step of the way to tell if I was done, and then if it was successful to > join the resultant list back into a string.) > _________________________________________________ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/users _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
