How to get substring of NSString?

Question

If I want to get a value from the NSString @"value:hello World:value", what should I use?

The return value I want is @"hello World".

possible duplicate [search within NSstring](http://stackoverflow.com/questions/3771211/search-within-nsstring) or [Search through NSString using Regular Expression.](http://stackoverflow.com/questions/4353834/search-through-nsstring-using-regular-expression) — Black Frog, Apr 15 '11 at 11:48
I'm voting to close this question as unclear what your asking. There's no indication at all of exactly what is wanted here. Do you want to just return `"hello World"`? `return @"hello World"`. Do you want to return just what's between colons? Do you want to strip everything left of the left-most colon and everything right of the right-most colon? There is no clearly defined input-output criteria for this question (as we see with the resulting list of questions that all solve the problem with a wild array of approaches). — nhgrif, Aug 25 '15 at 12:55

score 162 · Accepted Answer · edited Feb 17 '16 at 23:13

Option 1:

NSString *haystack = @"value:hello World:value";
NSString *haystackPrefix = @"value:";
NSString *haystackSuffix = @":value";
NSRange needleRange = NSMakeRange(haystackPrefix.length,
                                  haystack.length - haystackPrefix.length - haystackSuffix.length);
NSString *needle = [haystack substringWithRange:needleRange];
NSLog(@"needle: %@", needle); // -> "hello World"

Option 2:

NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"^value:(.+?):value$" options:0 error:nil];
NSTextCheckingResult *match = [regex firstMatchInString:haystack options:NSAnchoredSearch range:NSMakeRange(0, haystack.length)];
NSRange needleRange = [match rangeAtIndex: 1];
NSString *needle = [haystack substringWithRange:needleRange];

This one might be a bit over the top for your rather trivial case though.

Option 3:

NSString *needle = [haystack componentsSeparatedByString:@":"][1];

This one creates three temporary strings and an array while splitting.

All snippets assume that what's searched for is actually contained in the string.

It cried on NSAnchoredSearch... maybe NSMatchingAnchored is better. — Jonny, Jan 05 '17 at 09:52

score 76 · Answer 2 · answered Apr 27 '13 at 15:22

76

Here's a slightly less complicated answer:

NSString *myString = @"abcdefg";
NSString *mySmallerString = [myString substringToIndex:4];

See also substringWithRange and substringFromIndex

answered Apr 27 '13 at 15:22

Shaun Neal

1,183
1
10
12

2

Sorry, this doesn't answer the question (how to get a substring from the middle of a string). – Monolo Apr 27 '13 at 15:42
what does that return – Chicowitz Sep 18 '18 at 16:41

score 18 · Answer 3 · answered Oct 01 '13 at 18:15

18

Here's a simple function that lets you do what you are looking for:

- (NSString *)getSubstring:(NSString *)value betweenString:(NSString *)separator
{
    NSRange firstInstance = [value rangeOfString:separator];
    NSRange secondInstance = [[value substringFromIndex:firstInstance.location + firstInstance.length] rangeOfString:separator];
    NSRange finalRange = NSMakeRange(firstInstance.location + separator.length, secondInstance.location);

    return [value substringWithRange:finalRange];
}

Usage:

NSString *myName = [self getSubstring:@"This is my :name:, woo!!" betweenString:@":"];

answered Oct 01 '13 at 18:15

Garett

552
6
15

1

In case it's illuminating, I can tell you my reason for voting up the other answer. I would rather write two lines of code than six. – Le Mot Juiced Nov 15 '13 at 17:01
2

The problem is that those two lines of code only solve a specific case that will never exist for anyone -- probably not even for the person that asked it. – Garett Nov 19 '13 at 22:39
`getSubstring:…` should be called `substringInString:…` as you're not passing a substring to it and methods starting with `get…` are usually expected to be passed a buffer pointer to write to. `substringFromIndex:` creates an intermediate substring, which is unnecessary, that's what `rangeOfString:options:range:` is for. Last by wrapping the unsafe snippet in a supposedly generic method you're masking a bug: If the separator exists a single or less times in the string you'll get an out of range exception. – Regexident May 07 '14 at 15:57

Abhishek Mishra · Answer 4 · 2016-06-01T05:31:06.707

14

Use this also

NSString *ChkStr = [MyString substringWithRange:NSMakeRange(5, 26)];

Note - Your NSMakeRange(start, end) should be NSMakeRange(start, end- start);

edited Jun 01 '16 at 05:31

answered Jun 01 '16 at 04:37

Abhishek Mishra

1,625
16
32

score 13 · Answer 5 · answered Jul 07 '14 at 18:41

Here is a little combination of @Regexident Option 1 and @Garett answers, to get a powerful string cutter between a prefix and suffix, with MORE...ANDMORE words on it.

NSString *haystack = @"MOREvalue:hello World:valueANDMORE";
NSString *prefix = @"value:";
NSString *suffix = @":value";
NSRange prefixRange = [haystack rangeOfString:prefix];
NSRange suffixRange = [[haystack substringFromIndex:prefixRange.location+prefixRange.length] rangeOfString:suffix];
NSRange needleRange = NSMakeRange(prefixRange.location+prefix.length, suffixRange.location);
NSString *needle = [haystack substringWithRange:needleRange];
NSLog(@"needle: %@", needle);

Now this works! I tried Regixident's option 1, it didn't work for me. I can't think why. I've been searching for a solution to get a string inside a `````` tags in my project to make those strings italic. :) — Glenn Posadas, Jul 09 '18 at 18:35

How to get substring of NSString?

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