If-else: NSString

Question

I want to do the following thing: if country == "Россия", some actions.. But my if-else statement doesn't work. What do I should do? Thanks in advance. My code:

   NSLocale *locale = [NSLocale currentLocale];
        NSString *countryCode = [locale objectForKey:NSLocaleCountryCode];
        NSString *country = [locale displayNameForKey:NSLocaleCountryCode value: countryCode];
        NSLog(@"%@", country);

        if (country == @"Россия") {
            NSLog(@"GO RUSSIA");
        }
        else {
            NSLog(@"You are not russian");
        }

When you compare with `==` you're checking to see if the two pointers address the exact same object. `isEqual` checks to see if the two objects, even if not the same object, have essentially equal contents. — Hot Licks, Oct 22 '13 at 15:40
Sometimes I wonder whether I'm the only one reading the documentation when I have a doubt... — Gabriele Petronella, Oct 22 '13 at 16:08

score 8 · Answer 1 · answered Oct 22 '13 at 15:36

8

You need to use comparison methods from NSString:

if ([country isEqualToString: @"Россия"]) {
   ...
}

Simply using == will compare raw pointer values, not actual string values.

answered Oct 22 '13 at 15:36

Vladimir

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Thank you. Everything is true and works. :) – useboot Oct 22 '13 at 15:38
This rule acts with only NSString? – useboot Oct 22 '13 at 15:38
Not just with NSString, for example `NSNumber` has it's own `isEqualToNumber` method for doing comparison checks. – Nicholas Smith Oct 22 '13 at 15:40
Normally you should compare any obj-c objects using special methods (isEqual: or isEqualToSmth: - custom classes can define custom comparison methods). Comparing pointers will almost never work – Vladimir Oct 22 '13 at 15:40
The only time you want to use `==` with objects is if you want to test if two variables point to the same instance. – Lance Oct 22 '13 at 15:49
1

`NSNumber` in particular can be confusing here, since some, but not all, `NSNumber`s are singletons. So you can have code where `num1 == num2` works fine when num1 and num2 are 12, but fails when they're 13. Always use the `isEqual` methods. – Rob Napier Oct 22 '13 at 16:02
Also you can use `==` to compare `NSString const *`, but again it's better to use `isEqualToString` to prevent stupid mistakes. – Gabriele Petronella Oct 22 '13 at 16:14

score 3 · Answer 2 · answered Oct 22 '13 at 15:36

3

This:

if (country == @"Россия")

Is not the way to compare a NSString.

Try this:

if ([country isEqualToString:@"Россия"])

answered Oct 22 '13 at 15:36

Antonio MG

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Hussain Shabbir · Answer 3 · 2013-10-22T16:19:46.000

0

If you want to write the condition in == then only integer or Bool variable you can write And if you want to compare string contents then use equaltostring api below

if ([country isEqualToString: @"Россия"]) {
}

edited Oct 22 '13 at 16:19

answered Oct 22 '13 at 15:59

Hussain Shabbir

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-1. comparing lengths is plain wrong in this case. – Gabriele Petronella Oct 22 '13 at 16:01
Because integer value you can compare in == .so above we are comparing length which is integer value – Hussain Shabbir Oct 22 '13 at 16:01
Because the OP wants to compare the content of the string. You "solution" would return `YES` even for the two strings `@"Russia"` and `@"FooBar"` – Gabriele Petronella Oct 22 '13 at 16:05
Ok got it gabriel thanks i forgot to think this scenario. Hence updated the answer – Hussain Shabbir Oct 22 '13 at 16:06
@gabriel updated the answer please have a look and let me know still i am going on wrongtrack – Hussain Shabbir Oct 22 '13 at 16:09
A part from the yoda-style of the sentence, what you are saying is sort of correct, even though non complete, not explicative and not an answer to the OP's problem. – Gabriele Petronella Oct 22 '13 at 16:11
Ok you managed to copy one of the answers above. At least is correct now. – Gabriele Petronella Oct 22 '13 at 16:27
@gabriel, lol i was not copying but only not able to express correctly:) – Hussain Shabbir Oct 22 '13 at 16:36

If-else: NSString

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