Question

How do I shorten the following code by executing it in a for loop?

NSArray *images = [NSArray arrayWithObjects:
                         [UIImage imageNamed:@"z1.png"],
                         [UIImage imageNamed:@"z2.png"],
                         [UIImage imageNamed:@"z3.png"],
                         [UIImage imageNamed:@"z4.png"],
                         [UIImage imageNamed:@"z5.png"],
                         [UIImage imageNamed:@"z6.png"],
                         [UIImage imageNamed:@"z7.png"],
                         [UIImage imageNamed:@"z8.png"],
                         [UIImage imageNamed:@"z9.png"],
                         [UIImage imageNamed:@"z10.png"],
                         [UIImage imageNamed:@"z11.png"],
                         [UIImage imageNamed:@"z12.png"],
                         [UIImage imageNamed:@"z13.png"],
                         [UIImage imageNamed:@"z14.png"],
                         [UIImage imageNamed:@"z15.png"],
                         [UIImage imageNamed:@"z16.png"],
                         [UIImage imageNamed:@"z17.png"],
                         [UIImage imageNamed:@"z18.png"],
                         [UIImage imageNamed:@"z19.png"],
                         nil];

Answer 1

The magic is in NSMutableArray as @Teak mentioned in the comment. In fact, there is a mutable version for all container classes like, like NSString, NSDictionary, NSSet, etc.

NSMutableArray *images = [NSMutableArray array];

for (NSUInteger i = 1; i <= 19; i++) {
    NSString *imageName = [NSString stringWithFormat:@"z%d.png", i];
    [images addObject:[UIImage imageNamed:imageName];
}