Question

I’m trying to write the equivalent of strchr, but with NSStrings… I’ve currently got this:

Boolean nsstrchr(NSString* s, char c)
{
    NSString *tmps = [NSString stringWithFormat: @"%c", c];
    NSCharacterSet *cSet = [NSCharacterSet characterSetWithCharactersInString: tmps];
    NSRange rg = [s rangeOfCharacterFromSet: cSet];
    return rg.location != NSNotFound;
}

This seems needlessly complex… Is there a way to do this (preferably, one that doesn’t involve turning the NSString into a cstring which doubles the run time, or writing it myself using characterAtIndex:… Am I missing some obvious method in the NSString description?

Answer 1

KennyTM has already noted (in a comment) that you can use -[NSString rangeOfString:] instead of -[NSString rangeOfCharacterFromSet]. I don’t mean to steal his helpful answer, but I wanted to point out that you can wrap this up in a category on NSString to make it easier to use:

@interface NSString (AdditionalStringOps)
- (BOOL) containsCharacter:(char) c;
@end

@implementation NSString (AdditionalStringOps)

- (BOOL) containsCharacter:(char) c
{
    NSString *tmp = [NSString stringWithFormat:@"%c", c];
    return [self rangeOfString:tmp].location != NSNotFound;
}

@end

And then you can use it like so:

if ([myString containsCharacter:'A']) {
    // Do stuff...
}