找出陣列中的元素數量
placeholderCopyNSArray *myColors = [NSArray arrayWithObjects: @"Red", @"Green", @"Blue", @"Yellow", nil];
NSLog (@"Number of elements in array = %lu", [myColors count]);
placeholderCopyNSArray *myColors = [NSArray arrayWithObjects: @"Red", @"Green", @"Blue", @"Yellow", nil];
NSLog (@"Number of elements in array = %lu", [myColors count]);