Differences between [NSArray arrayWithArray:] and [NSArray copy]

Question

lately I work much with arrays and I\'m wonder.. what\'s diffrences between those two lines.

NSArray *array = [NSArray arrayWithArray:someArray];

Answer 1

NSMutableArray *arr = [NSMutableArray array];
for ( int i = 0; i < 10000; i ++)
{
    [arr addObject:@(i*1000000ULL)];
}
// MARK
// arr = (id)[NSArray arrayWithArray:arr];

NSTimeInterval t = [NSDate timeIntervalSinceReferenceDate];
NSArray *res = nil;
for ( int i = 0; i < 10000; i ++)
{
    res = [arr copy];
}
NSLog(@"time A: %f", [NSDate timeIntervalSinceReferenceDate] - t);
t = [NSDate timeIntervalSinceReferenceDate];
for ( int i = 0; i < 10000; i ++)
{
    res = [NSArray arrayWithArray:arr];
}
NSLog(@"time B: %f", [NSDate timeIntervalSinceReferenceDate] - t);

time A: 1.572795, time B: 1.539150, B [NSArray arrayWithArray:] always faster but time difference very small. But if we uncomment "MARK" and get copy from NSArray instead NSMutableArray we will have other runtime A: 0.000473 time B: 1.548400 result: ~3200x times faster