CocoaDev

Here is some code that removes white space from a string, like new lines, tabs, and double spaces (not single spaces). It’s intended as to be used in an NSString category. Example could be [@” h\nello\r” removeWhiteSpace] would return @”hello”

Note: this is not to use as a trim function, for that use CFStringTrimWhitespace ((CFMutableStringRef) yourStringHere);

Enjoy!! –KevinWojniak

- (NSString *)removeWhiteSpace {
NSMutableString *new = [NSMutableString string];
NSArray *whites = [NSArray arrayWithObjects:@"\r", @"\n", @"  ", @"\t", nil];
NSEnumerator *e = [whites objectEnumerator];
id item;

[new setString:self];

while (item = [e nextObject]) {
    NSRange r = [new rangeOfString:item];
    
    while (r.location != NSNotFound) {
        [new replaceOccurrencesOfString:item withString:@"" options:nil range:NSMakeRange(0, [new length])];
        r = [new rangeOfString:item];
    }
}

return new;    }

Sounds nifty. Could be useful for someone trying to write an interpreter in Cocoa. –OwenAnderson

What you’re doing is removing double spaces entirely - so if I wrote “This is a test.” I’d get back “This is atest.” Since often when removing whitespace this isn’t quite ideal, the following added in in place of the two-spacer works:

while([theString replaceOccurrencesOfString:@” “ withString:@” “ options:NSLiteralSearch range:NSMakeRange(0, [theString length])]);

This will reduce all blank space down to a single space, which is often more what is wanted. Hope this helps –DanKeen

Ah yes that was a bug - thanks for fixing it! –KevinWojniak

Another option for a trimming function is NSString’s method stringByTrimmingCharactersInSet: –SeanUnderwood —- I’m pretty sure that stringByTrimmingCharactersInSet: is quite a bit slower than NSMutableString’s replace occurrences method. Anyone know for sure?