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iOS Objective-C Basics (Retired) Foundation Framework NSArray

Judy Tsai
Judy Tsai
6,376 Points
Posted by Judy Tsai
Judy Tsai
6,376 Points

Can not create String pointing to array element directly

Hi,

I followed the steps to create the NSString *thang, but received

error: Semantic Issue: Initializing 'NSString *' with an expression of incompatible type 'NSArray'

The code looks like this

    NSArray *foo = [[NSArray alloc] initWithObjects: @"f", @"o", @"o", nil];
    NSLog(@"%@", foo);
    //use for loop to print individual item in array
    for (NSString *string in foo){
        NSLog(@"%@", string);        
    }
    NSString *thang = foo[2];
    NSLog(@"%@", thang);

What am I missing here?

Thank you!

4 Answers

Stone Preston
Stone Preston
42,016 Points
Stone Preston
Stone Preston
42,016 Points

maybe try:

NSString *thang = [foo objectAtIndex:2];
Judy Tsai
Judy Tsai
6,376 Points
Judy Tsai
Judy Tsai
6,376 Points

Hi, Stone,

That worked! Thank you!

I also ran on NSMutableArray, when I declare array and assign value like this:

NSMutableArray *lots = [[NSMutableArray alloc] init];
    lots[0] = @"bravo";
    lots[1] = @"lima";

I got the error of

Semantic Issue: Assigning to 'NSMutableArray' from incompatible type 'NSString *'

Do I need to declare individual NSString? Am I missing something here again?

Thank you so much for your help!

Stone Preston
Stone Preston
42,016 Points
Stone Preston
Stone Preston
42,016 Points

try creating the array as a literal and see if that makes a difference:

NSMutableArray *lots =@[];
    lots[0] = @"bravo";
    lots[1] = @"lima";
Judy Tsai
Judy Tsai
6,376 Points
Judy Tsai
Judy Tsai
6,376 Points

hmm..I tried that and it now gives me an additional error at declaration:

Unexpected '@' in program

Stone Preston
Stone Preston
42,016 Points
Stone Preston
Stone Preston
42,016 Points

what version of xcode are you using?

literal array syntax and indexing arrays using [] was added to objective c relatively recently. so that might be your issue

Judy Tsai
Judy Tsai
6,376 Points
Judy Tsai
Judy Tsai
6,376 Points

Hi, Stone,

You were correct, I tried the same code at home, which has a newer xcode and it worked fine!

Thank you for being patient and helpful for a newbie!