Rust: What is the difference between swap_remove and remove?

swap_remove — O(1) remove. remove — O(n) remove.

swap_remove:

• O(1) time.
• Changes order.
• For unordered.

remove:

• O(n) time.
• Preserves order.
• For ordered.

1let mut v = vec![1, 2, 3, 4, 5];
2v.swap_remove(1);  // O(1)
3// v: [1, 5, 3, 4]  (order changed)
4
5let mut v = vec![1, 2, 3, 4, 5];
6v.remove(1);  // O(n)
7// v: [1, 3, 4, 5]  (order preserved)

Key: swap_remove for speed, remove for order.