Combining multiple NSArrays

How can I combine multiple NSArrays into one array with alternating values? For example.

Array One: Orange, Apple, Pear

Array Two: Tree, Shrub, Flower

Array Three: Blue, Green, Yellow

开发者_运维技巧The final array would need to be: Orange, Tree, Blue, Apple, Shrub, Green, etc

[@[@[@1,@2],@[@3,@4],@[@5,@6]] valueForKeyPath:@"@unionOfArrays.self"]

So once you have a array of arrays you call unionOfArrays collection operator.

Assuming the arrays are all of the same length:

NSUInteger numberOfArrays = 3;
NSUInteger arrayLength = [arrayOne length];
NSMutableArray *finalMutableArray = [NSMutableArray arrayWithCapacity:(arrayLength * numberOfArrays)];
for (NSUInteger index = 0; index < arrayLength; index++) {
    [finalMutableArray addObject:[arrayOne objectAtIndex:index]];
    [finalMutableArray addObject:[arrayTwo objectAtIndex:index]];
    [finalMutableArray addObject:[arrayThree objectAtIndex:index]];
}
NSArray *finalArray = [NSArray arrayWithArray:finalMutableArray];

You will probably want to test that the arrays are of the same length. You cannot add nil to an NSMutableArray or NSArray. You can add an NSNull placeholder, but it's probably better to check your input.

If you have array of arrays

NSArray *arrayOfArrays = ...;
NSMutableArray *oneArray = [NSMutableArray array];
for (NSArray *tmpArray in arrayOfArrays) {
    [oneArray addObjectsFromArray:tmpArray];
}