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Slight modification to the as_ref example of std::option::Option #48509

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Merged
merged 3 commits into from
Mar 6, 2018
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Slight modification to the as_ref example of std::option::Option #48509

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bbd64b2
Slight modification to the as_ref example of std::option::Option
Phlosioneer Feb 24, 2018
e8904f9
Change the example string to something arbitrary
Phlosioneer Feb 25, 2018
b7b3498
Fix doctest failure
Phlosioneer Feb 27, 2018
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4 changes: 2 additions & 2 deletions src/libcore/option.rs
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Expand Up @@ -233,10 +233,10 @@ impl<T> Option<T> {
/// [`usize`]: ../../std/primitive.usize.html
///
/// ```
/// let num_as_str: Option<String> = Some("10".to_string());
/// let num_as_str: Option<String> = Some("12".to_string());
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@neandrake neandrake Feb 25, 2018 •
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To address the problem more directly it might make sense to change this completely -- the fact that the string contents are numbers is irrelevant. Maybe instead

let text: Option<String> = Some("Hello, World!".to_string());
let text_length: Option<usize> = text.as_ref().map(|t| t.len());

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That's a good idea. I'll change that.

/// // First, cast `Option<String>` to `Option<&String>` with `as_ref`,
/// // then consume *that* with `map`, leaving `num_as_str` on the stack.
/// let num_as_int: Option<usize> = num_as_str.as_ref().map(|n| n.len());
/// let num_length: Option<usize> = num_as_str.as_ref().map(|n| n.len());
/// println!("still can print num_as_str: {:?}", num_as_str);
/// ```
#[inline]
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