Map change all in Objective-C

To change all the elements of an array in Objective-C, you need to iterate over each element of the array and replace it with a new value.

Here's an example:

NSMutableArray *myArray = [[NSMutableArray alloc] initWithObjects:@"apple", @"banana", @"orange", nil];

In the above code, we have created an NSMutableArray named myArray with some initial values.

Now, let's say we want to change all the elements of this array to uppercase. We can achieve this by iterating over each element and using the uppercaseString method of NSString to convert each element to uppercase.

for (int i = 0; i < [myArray count]; i++) {
    NSString *originalString = [myArray objectAtIndex:i];
    NSString *uppercaseString = [originalString uppercaseString];
    [myArray replaceObjectAtIndex:i withObject:uppercaseString];
}
NSLog(@"%@", myArray);

In the above code, we are using a for loop to iterate over each element of myArray. For each element, we are retrieving the original string using the objectAtIndex method, converting it to uppercase using uppercaseString, and replacing the original string with the uppercase string using the replaceObjectAtIndex method.

After all the elements have been converted to uppercase, we simply print the modified array using the NSLog statement.

Output:

(

    APPLE,

    BANANA,

    ORANGE

)