Ordering arrays of sorted Int

Question

Is there a short & clean way to compare 2 arrays of sorted Int ?

Like [1,4,7] should come before [1,5] but after [1,2,3

Answer 1

A possible implementation (explanations inline):

func < <T where T: Comparable>(lhs: [T], rhs: [T]) -> Bool {

    // Compare all elements up to common length, return
    // if a difference is found:
    for (l, r) in zip(lhs, rhs) {
        if l < r { return true }
        if l > r { return false }
    }
    // All common elements are equal, check if rhs is "longer":
    return lhs.count < rhs.count
}

Example:

print([1,4,7] < [1,5])      // true
print([1,4,7] < [1,2,3,8])  // false
print([1,4,7] < [1,4,7,8])  // true (left array is shorter)
print([1,4,7] < [1,4,7])    // false (arrays are equal)