What is the syntax for checking if two strings are the same in Objective C

Question

What is the syntax for checking if strings are identical?

in Java it is: string1.equals(string2);

but what is it in objective C?

I assume you don't actually want to check if they are identical or are the same string but actually want to check if they have the same contents. — David Schwartz, Aug 01 '12 at 12:30
Yeah, just if they have the same contents, in my code I know that they are different values. — Logan S., Aug 01 '12 at 12:31

Seva Alekseyev · Answer 1 · 2012-08-01T13:08:20.057

2

NSString *String1, *String2;
if([String1 compare: String2] == NSOrderedSame)
    //They are the same

NSOrderedSame is defined as zero, so you can write

if(![String1 compare: String2])
    //Equals

edited Aug 01 '12 at 13:08

answered Aug 01 '12 at 12:29

Seva Alekseyev

59,826
25
160
281

Is there any difference between `isEqualToString:` and `compare:` ? – ThomasCle Aug 01 '12 at 12:37
It's shorter. Also, it's a natural fit for longtime users of `strcmp`. – Seva Alekseyev Aug 01 '12 at 13:08
2

`-compare:` will give you a bad result if either `self` or the argument is `nil`. So you should check for `nil` beforehand and do special processing if your use case includes potential `nil` objects. – Jonathan Grynspan Aug 01 '12 at 13:12

score 2 · Answer 2 · answered Aug 01 '12 at 12:29

2

Use the specific string equality message

[string1 isEqualToString: string2]

answered Aug 01 '12 at 12:29

waldrumpus

2,540
18
44

score 1 · Answer 3 · answered Aug 01 '12 at 12:29

1

You need to use isEqualToString.

 if ( [stringOne isEqualToString: stringTwo] ) { }

answered Aug 01 '12 at 12:29

Mahesh

34,573
20
89
115

score 1 · Accepted Answer · edited Aug 01 '12 at 13:07

You'll need to use isEqualToString for the most accurate results. I've included a couple examples on how to use it.

NSString *aString = foo;
NSString *bString = bar;
if ([aString isEqualToString:bString]) {
    NSLog("Match");
}
else NSLog("No Match");
//No match.

NSString *aString = foo;
NSString *bString = bar;
if ([aString isEqualToString:@"foo"]) {
    NSLog("Double Foo!");
}
else NSLog("No Match");
//Double Foo!

NSString *aString = foo;
NSString *bString = bar;
if (![aString isEqualToString:bString]) {
    NSLog("No Match");
}
else NSLog("Match");
//No Match

What is the syntax for checking if two strings are the same in Objective C

4 Answers4