Objective C: What's the easiest way to determine if a substring exists within an NSString?

Question

In PHP (which is what I'm most familiar with) it's a one line expression:

strpos('abc', 'b') !== false

What's the Objective C equivalent?

Does this help? http://www.techotopia.com/index.php/Working_with_String_Objects_in_Objective-C#Searching_for_a_Substring — jeffff, Jul 13 '12 at 18:42
The Cocoa classes are fairly well-documented. You're obviously encouraged to take a look at them any time you need something. — zneak, Jul 13 '12 at 18:43
@zneak I totally agree but a simple question isn't necessarily a bad question - especially considering how contrived some people's solutions are to simple questions. Documenting good answers to simple questions is of benefit to the community. Proof in point (a post I made the other day): http://stackoverflow.com/questions/11439180/whats-the-easiest-way-to-remove-empty-nsstrings-from-an-nsarray Nobody should be writing code equal to some of the bad answers. Having the simple answer documented is ultimately a good thing. — John Erck, Jul 13 '12 at 18:54

score 7 · Accepted Answer · answered Jul 13 '12 at 18:42

7

[@"abc" rangeOfString:@"b"].location != NSNotFound

answered Jul 13 '12 at 18:42

Parag Bafna

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score 3 · Answer 2 · answered Jul 13 '12 at 18:48

I think categories can be use to package up pieces of functionality like this very nicely.

@interface NSString (ContainsString)
- (BOOL)containsString:(NSString *)string;
@end

@implementation NSString (ContainsString)
- (BOOL)containsString:(NSString *)string
{
    NSRange range = [self rangeOfString:string options:NSCaseInsensitiveSearch];
    return range.location != NSNotFound;
}
@end

When used, it makes the meaning very clear.

if ([@"this is a string" containsString:@"a string"]) {
    …
}

In most projects this would be a part of a larger string method category and not it's own one-method category.

score 0 · Answer 3 · answered Jul 13 '12 at 18:43

- (NSRange)rangeOfString:(NSString *)aString

Return Value An NSRange structure giving the location and length in the receiver of the first occurrence of aString. Returns {NSNotFound, 0} if aString is not found or is empty (@"").

You can find more helpful string manipulation functions in the NSString Class Reference

Objective C: What's the easiest way to determine if a substring exists within an NSString?

3 Answers3