macOS Can you help me understand isEqualToString: ?

"isEqualToString:" is a method which takes a pointer ("aString") to a NSString object and compares it to the NSString object it was called on.

Here "thing1" is a pointer to a NSString object and we use it's member method "isEqualToString:" to compare it with the NSString object "thing2".

So "thing1" isn't an argument but an object which has a member method (or function if that's easier) called "isEqualToString:"

How About This

I'm having the same problem but it does not work, can you tell me what's wrong. (note:test 3 is the output from the keyboard dictionary it's a frame reference of the keyboard view.)


NSString *test3=[userInfo valueForKey:UIKeyboardFrameEndUserInfoKey];
NSString *test2 = @"NSRect: {{0, 217}, {320, 263}}";


NSLog(@"value is-%@",test3);
NSLog(@"string is-%@",test2);

NSlog output is…. you see they are both equal testing should evaluate to true

2011-01-29 09:48:30.314 APFA5[15478:207] value is-NSRect: {{0, 217}, {320, 263}}
2011-01-29 09:48:30.315 APFA5[15478:207] string is-NSRect: {{0, 217}, {320, 263}}

but if I evaluate with...

if ([test2 isEqualToString:test3]){

NSLog(@"TRUE");
}
else
{
NSLog(@"FALSE");
}

NSLog output becomes…..

2011-01-29 09:58:25.300 APFA5[15701:207] value is-NSRect: {{0, 217}, {320, 263}}
2011-01-29 09:58:25.301 APFA5[15701:207] string is-NSRect: {{0, 217}, {320, 263}}
2011-01-29 09:58:25.301 APFA5[15701:207] FALSE

it evaluates as FALSE WHY, WHY, WHY, WHY!!!!!!!!! HOW DO I COMPARE THESE NSString values?

ALEXROD said:

I'm having the same problem but it does not work, can you tell me what's wrong. (note:test 3 is the output from the keyboard dictionary it's a frame reference of the keyboard view.)


NSString *test3=[userInfo valueForKey:UIKeyboardFrameEndUserInfoKey];
NSString *test2 = @"NSRect: {{0, 217}, {320, 263}}";


NSLog(@"value is-%@",test3);
NSLog(@"string is-%@",test2);

NSlog output is…. you see they are both equal testing should evaluate to true

2011-01-29 09:48:30.314 APFA5[15478:207] value is-NSRect: {{0, 217}, {320, 263}}
2011-01-29 09:48:30.315 APFA5[15478:207] string is-NSRect: {{0, 217}, {320, 263}}

but if I evaluate with...

if ([test2 isEqualToString:test3]){

NSLog(@"TRUE");
}
else
{
NSLog(@"FALSE");
}

NSLog output becomes…..

2011-01-29 09:58:25.300 APFA5[15701:207] value is-NSRect: {{0, 217}, {320, 263}}
2011-01-29 09:58:25.301 APFA5[15701:207] string is-NSRect: {{0, 217}, {320, 263}}
2011-01-29 09:58:25.301 APFA5[15701:207] FALSE

it evaluates as FALSE WHY, WHY, WHY, WHY!!!!!!!!! HOW DO I COMPARE THESE NSString values?

Click to expand...

NSRect is not a string, so you cant make a literal comparison. You may try isEqualTo instead, or comparing the actual values of the NSRect with each other.

Thanks Sayer

Thanks Sayer I appreciate your response. You gave me a good idea to compare frames instead of strings.

I tried isEqualToString but it always evaluates to FALSE even both values are equal. (Probably comparing memory pointers and not values)

But What I cant understand is that both values are output by NSLog as strings to the console, so how does NSLog do that. That would equalize both values so they can be compared...

Anyway thanks, again...

reply

Ah, I see, It says I was trying to stuff an Elephant into a Pickle jar. I printed out the page, thanks for the reference...