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0a815fd94b
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0a815fd94b |
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@ -4,11 +4,9 @@
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#[rustfmt::skip]
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#[allow(unused_variables, unused_assignments)]
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fn main() {
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let my_option: Option<&str> = None;
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// Assume that you don't know the value of `my_option`.
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// In the case of `Some`, we want to print its value.
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let my_option: Option<()> = None;
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if my_option.is_none() {
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println!("{}", my_option.unwrap());
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println!("{:?}", my_option.unwrap());
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}
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let my_arr = &[
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@ -29,21 +29,6 @@ impl ParsePosNonzeroError {
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}
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}
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// As an alternative solution, implementing the `From` trait allows for the
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// automatic conversion from a `ParseIntError` into a `ParsePosNonzeroError`
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// using the `?` operator, without the need to call `map_err`.
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//
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// ```
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// let x: i64 = s.parse()?;
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// ```
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//
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// Traits like `From` will be dealt with in later exercises.
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impl From<ParseIntError> for ParsePosNonzeroError {
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fn from(err: ParseIntError) -> Self {
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ParsePosNonzeroError::ParseInt(err)
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}
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}
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#[derive(PartialEq, Debug)]
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struct PositiveNonzeroInteger(u64);
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@ -3,11 +3,11 @@ use std::mem;
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#[rustfmt::skip]
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#[allow(unused_variables, unused_assignments)]
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fn main() {
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let my_option: Option<&str> = None;
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let my_option: Option<()> = None;
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// `unwrap` of an `Option` after checking if it is `None` will panic.
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// Use `if-let` instead.
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if let Some(value) = my_option {
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println!("{value}");
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println!("{value:?}");
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}
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// A comma was missing.
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