Rust: What is the difference between contains and position?

contains — check existence. position — find index.

contains:

• Returns bool.
• No index.
• Simple check.

position:

• Returns Option<usize>.
• Provides index.
• For finding.

1let v = vec![1, 2, 3, 4, 5];
2
3// contains: true
4let has_three = v.contains(&3);
5
6// position: Some(2)
7let pos = v.iter().position(|&x| x == 3);

Key: contains for existence, position for index.