===============
Rust Cheatsheet
===============

.. highlight:: rust

字符串类型互转 [#]_
===================

::

   let s: String = ...
   let st: &str = ...
   let u: &[u8] = ...
   let b: [u8; 3] = b"foo"
   let v: Vec<u8> = ...
   let os: OsString = ...
   let ost: OsStr = ...

========== ========== ================================================= =======================================
From       To         Use                                               Comment
========== ========== ================================================= =======================================
`&str`     `String`    `String::from(st)`
`&str`     `&[u8]`     `st.as_bytes()`
`&str`     `Vec<u8>`   `st.as_bytes().to_owned()`                       via `&[u8]`
`&str`     `&OsStr`    `OsStr::new(st)`

`String`   `&str`      `&s`                                             alt. `s.as_str()`
`String`   `&[u8]`     `s.as_bytes()`
`String`   `Vec<u8>`   `s.into_bytes()`
`String`   `OsString`  `OsString::from(s)`

`&[u8]`    `&str`      `str::from_utf8(u).unwrap()`
`&[u8]`    `String`    `String::from_utf8(u).unwrap()`
`&[u8]`    `Vec<u8>`   `u.to_owned()`
`&[u8]`    `&OsStr`    `OsStr::from_bytes(u)`                           `use std::os::unix::ffi::OsStrExt`;

`[u8; 3]`  `&[u8]`     `&b[..]`                                         byte literal
`[u8; 3]`  `&[u8]`     `"foo".as_bytes()`                               alternative via utf8 literal

`Vec<u8>`  `&str`      `str::from_utf8(&v).unwrap()`                    via `&[u8]`
`Vec<u8>`  `String`    `String::from_utf8(v)`
`Vec<u8>`  `&[u8]`     `&v`
`Vec<u8>`  `OsString`  `OsString::from_vec(v)`                          `use std::os::unix::ffi::OsStringExt`;

`&OsStr`   `&str`      `ost.to_str().unwrap()`
`&OsStr`   `String`    `ost.to_os_string().into_string().unwrap()`      via `OsString`
`&OsStr`   `Cow<str>`  `ost.to_string_lossy()`                          Unicode replacement characters
`&OsStr`   `OsString`  `ost.to_os_string()`
`&OsStr`   `&[u8]`     `ost.as_bytes()`                                 `use std::os::unix::ffi::OsStringExt`;

`OsString` `String`    `os.into_string().unwrap()`                      returns original `OsString` on failure
`OsString` `&str`      `os.to_str().unwrap()`
`OsString` `&OsStr`    `os.as_os_str()`
`OsString` `Vec<u8>`   `os.into_vec()`                                  `use std::os::unix::ffi::OsStringExt;`
========== ========== ================================================= =======================================

.. [#] `Converting between different String types in Rust`__

__ https://profpatsch.de/notes/rust-string-conversions