stringByTrimmingCharactersInSet: - not tripping a disallowed '%'?

Question

For some odd reason, my stringByTrimmingCharacterInSet: allows the '%' through.

Why?

Simple code that demonstrates the issue (meant to extra a phone # from text):

    NSString * allowedSet = @"01234567890+-#";
    NSCharacterSet * disallowedSet =[[NSCharacterSet characterSetWithCharactersInString:allowedSet] invertedSet];

    in = @"+31%121212abc";
    out = [in  stringByTrimmingCharactersInSet:disallowedSet];

I would have expected as the output

... In  : +31%121212abc
... Out : +31121212

but I am getting:

... In  : +31%121212abc
... Out : +31%121212

Why is that? It seems to work for pretty much all other chars. Is the '%' special - or is this some odd URL related issue?

Trimming work only at the beginning and and the end of the string, no? — Larme, Jun 04 '15 at 12:36
Aye - I realised that seconds after writing it - and answered my own question. — Dirk-Willem van Gulik, Jun 04 '15 at 12:36
possible duplicate of [stringByTrimmingCharactersInSet: is not removing characters in the middle of the string](http://stackoverflow.com/questions/5581141/stringbytrimmingcharactersinset-is-not-removing-characters-in-the-middle-of-the) — Larme, Jun 04 '15 at 12:37

Dirk-Willem van Gulik · Answer 1 · 2015-06-04T12:37:53.323

I am trimming the string; as opposed to replacing chars. So it ignores those not at the start or end; i.e. the chars in the middle of the string. Using stringByReplacingCharactersInSet: resolves this nicely.

@interface NSString (inefficientStringByRemovingCharactersInSet)
- (NSString *)stringByRemovingCharactersInSet:(NSCharacterSet *)characterSet;
@end

@implementation NSString (inefficientStringByRemovingCharactersInSet)
- (NSString *)stringByRemovingCharactersInSet:(NSCharacterSet *)characterSet {
    return [[self componentsSeparatedByCharactersInSet:characterSet]
       componentsJoinedByString:@""];
}
@end

stringByTrimmingCharactersInSet: - not tripping a disallowed '%'?

1 Answers1