Concatenation of two arrays in Objective-C

Question

How to concatenate two arrays into a single array in Objective-C?

Answer 1

With immutable arrays:

NSArray *arr1 = @[@(1), @(2), @(3)];
NSArray *arr2 = @[@(4), @(5), @(6)];
NSArray *arr3 = [arr1 arrayByAddingObjectsFromArray:arr2];

or adding onto a mutable array:

NSArray *arr1 = @[@(1), @(2), @(3)];
NSArray *arr2 = @[@(4), @(5), @(6)];
NSMutableArray *arr3 = [NSMutableArray arrayWithArray:arr1];

[arr3 addObjectsFromArray:arr2];