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58 lines
1.0 KiB
Rust
58 lines
1.0 KiB
Rust
// option1.rs
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// This example panics because the second time it calls `pop`, the `vec`
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// is empty, so `pop` returns `None`, and `unwrap` panics if it's called
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// on `None`. Handle this in a more graceful way than calling `unwrap`!
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// Scroll down for hints :)
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pub fn pop_too_much() -> bool {
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let mut list = vec![3];
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let last = list.pop().unwrap();
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println!("The last item in the list is {:?}", last);
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let second_to_last = list.pop().unwrap();
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println!(
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"The second-to-last item in the list is {:?}",
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second_to_last
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);
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true
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn should_not_panic() {
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assert!(pop_too_much());
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}
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}
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// Try using a `match` statement where the arms are `Some(thing)` and `None`.
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// Or set a default value to print out if you get `None` by using the
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// function `unwrap_or`.
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// Or use an `if let` statement on the result of `pop()` to both destructure
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// a `Some` value and only print out something if we have a value!
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