1.0.0[−][src]Trait std::convert::From

pub trait From<T> {
    fn from(T) -> Self;
}

Used to do value-to-value conversions while consuming the input value. It is the reciprocal of Into.

One should always prefer implementing From over Into because implementing From automatically provides one with a implementation of Into thanks to the blanket implementation in the standard library.

Only implement Into if a conversion to a type outside the current crate is required. From cannot do these type of conversions because of Rust's orphaning rules. See Into for more details.

Prefer using Into over using From when specifying trait bounds on a generic function. This way, types that directly implement Into can be used as arguments as well.

The From is also very useful when performing error handling. When constructing a function that is capable of failing, the return type will generally be of the form Result<T, E>. The From trait simplifies error handling by allowing a function to return a single error type that encapsulate multiple error types. See the "Examples" section and the book for more details.

Note: This trait must not fail. If the conversion can fail, use TryFrom.

Generic Implementations

Examples

String implements From<&str>:

An explicit conversion from a &str to a String is done as follows:

let string = "hello".to_string();
let other_string = String::from("hello");

assert_eq!(string, other_string);Run

While performing error handling it is often useful to implement From for your own error type. By converting underlying error types to our own custom error type that encapsulates the underlying error type, we can return a single error type without losing information on the underlying cause. The '?' operator automatically converts the underlying error type to our custom error type by calling Into<CliError>::into which is automatically provided when implementing From. The compiler then infers which implementation of Into should be used.

use std::fs;
use std::io;
use std::num;

enum CliError {
    IoError(io::Error),
    ParseError(num::ParseIntError),
}

impl From<io::Error> for CliError {
    fn from(error: io::Error) -> Self {
        CliError::IoError(error)
    }
}

impl From<num::ParseIntError> for CliError {
    fn from(error: num::ParseIntError) -> Self {
        CliError::ParseError(error)
    }
}

fn open_and_parse_file(file_name: &str) -> Result<i32, CliError> {
    let mut contents = fs::read_to_string(&file_name)?;
    let num: i32 = contents.trim().parse()?;
    Ok(num)
}Run

Required methods

fn from(T) -> Self

Performs the conversion.

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Implementors

impl From<Infallible> for TryFromSliceError[src]

impl From<Infallible> for TryFromIntError[src]

impl From<ErrorKind> for Error[src]

Intended for use for errors not exposed to the user, where allocating onto the heap (for normal construction via Error::new) is too costly.

fn from(kind: ErrorKind) -> Error[src]

Converts an ErrorKind into an Error.

This conversion allocates a new error with a simple representation of error kind.

Examples

use std::io::{Error, ErrorKind};

let not_found = ErrorKind::NotFound;
let error = Error::from(not_found);
assert_eq!("entity not found", format!("{}", error));Run

impl From<[u16; 8]> for IpAddr[src]

fn from(segments: [u16; 8]) -> IpAddr[src]

Creates an IpAddr::V6 from an eight element 16-bit array.

Examples

use std::net::{IpAddr, Ipv6Addr};

let addr = IpAddr::from([
    525u16, 524u16, 523u16, 522u16,
    521u16, 520u16, 519u16, 518u16,
]);
assert_eq!(
    IpAddr::V6(Ipv6Addr::new(
        0x20d, 0x20c,
        0x20b, 0x20a,
        0x209, 0x208,
        0x207, 0x206
    )),
    addr
);Run

impl From<[u16; 8]> for Ipv6Addr[src]

impl From<[u8; 4]> for IpAddr[src]

fn from(octets: [u8; 4]) -> IpAddr[src]

Creates an IpAddr::V4 from a four element byte array.

Examples

use std::net::{IpAddr, Ipv4Addr};

let addr = IpAddr::from([13u8, 12u8, 11u8, 10u8]);
assert_eq!(IpAddr::V4(Ipv4Addr::new(13, 12, 11, 10)), addr);Run

impl From<[u8; 16]> for IpAddr[src]

fn from(octets: [u8; 16]) -> IpAddr[src]

Creates an IpAddr::V6 from a sixteen element byte array.

Examples

use std::net::{IpAddr, Ipv6Addr};

let addr = IpAddr::from([
    25u8, 24u8, 23u8, 22u8, 21u8, 20u8, 19u8, 18u8,
    17u8, 16u8, 15u8, 14u8, 13u8, 12u8, 11u8, 10u8,
]);
assert_eq!(
    IpAddr::V6(Ipv6Addr::new(
        0x1918, 0x1716,
        0x1514, 0x1312,
        0x1110, 0x0f0e,
        0x0d0c, 0x0b0a
    )),
    addr
);Run

impl From<[u8; 16]> for Ipv6Addr[src]

impl From<[u8; 4]> for Ipv4Addr[src]

fn from(octets: [u8; 4]) -> Ipv4Addr[src]

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::from([13u8, 12u8, 11u8, 10u8]);
assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);Run

impl From<bool> for i128[src]

Converts a bool to a i128. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i128::from(true), 1);
assert_eq!(i128::from(false), 0);Run

impl From<bool> for i16[src]

Converts a bool to a i16. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i16::from(true), 1);
assert_eq!(i16::from(false), 0);Run

impl From<bool> for i32[src]

Converts a bool to a i32. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i32::from(true), 1);
assert_eq!(i32::from(false), 0);Run

impl From<bool> for i64[src]

Converts a bool to a i64. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i64::from(true), 1);
assert_eq!(i64::from(false), 0);Run

impl From<bool> for i8[src]

Converts a bool to a i8. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i8::from(true), 1);
assert_eq!(i8::from(false), 0);Run

impl From<bool> for isize[src]

Converts a bool to a isize. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(isize::from(true), 1);
assert_eq!(isize::from(false), 0);Run

impl From<bool> for u128[src]

Converts a bool to a u128. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u128::from(true), 1);
assert_eq!(u128::from(false), 0);Run

impl From<bool> for u16[src]

Converts a bool to a u16. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u16::from(true), 1);
assert_eq!(u16::from(false), 0);Run

impl From<bool> for u32[src]

Converts a bool to a u32. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u32::from(true), 1);
assert_eq!(u32::from(false), 0);Run

impl From<bool> for u64[src]

Converts a bool to a u64. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u64::from(true), 1);
assert_eq!(u64::from(false), 0);Run

impl From<bool> for u8[src]

Converts a bool to a u8. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u8::from(true), 1);
assert_eq!(u8::from(false), 0);Run

impl From<bool> for usize[src]

Converts a bool to a usize. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(usize::from(true), 1);
assert_eq!(usize::from(false), 0);Run

impl From<bool> for AtomicBool[src]

fn from(b: bool) -> AtomicBool[src]

Converts a bool into an AtomicBool.

Examples

use std::sync::atomic::AtomicBool;
let atomic_bool = AtomicBool::from(true);
assert_eq!(format!("{:?}", atomic_bool), "true")Run

impl From<char> for u32[src]

fn from(c: char) -> u32[src]

Converts a char into a u32.

Examples

use std::mem;

fn main() {
    let c = 'c';
    let u = u32::from(c);
    assert!(4 == mem::size_of_val(&u))
}Run

impl From<f32> for f64[src]

Converts f32 to f64 losslessly.

impl From<i16> for isize[src]

Converts i16 to isize losslessly.

impl From<i16> for f32[src]

Converts i16 to f32 losslessly.

impl From<i16> for f64[src]

Converts i16 to f64 losslessly.

impl From<i16> for i128[src]

Converts i16 to i128 losslessly.

impl From<i16> for i32[src]

Converts i16 to i32 losslessly.

impl From<i16> for i64[src]

Converts i16 to i64 losslessly.

impl From<i16> for AtomicI16[src]

fn from(v: i16) -> AtomicI16[src]

Converts an i16 into an AtomicI16.

impl From<i32> for f64[src]

Converts i32 to f64 losslessly.

impl From<i32> for i128[src]

Converts i32 to i128 losslessly.

impl From<i32> for i64[src]

Converts i32 to i64 losslessly.

impl From<i32> for AtomicI32[src]

fn from(v: i32) -> AtomicI32[src]

Converts an i32 into an AtomicI32.

impl From<i64> for i128[src]

Converts i64 to i128 losslessly.

impl From<i64> for AtomicI64[src]

fn from(v: i64) -> AtomicI64[src]

Converts an i64 into an AtomicI64.

impl From<i8> for isize[src]

Converts i8 to isize losslessly.

impl From<i8> for f32[src]

Converts i8 to f32 losslessly.

impl From<i8> for f64[src]

Converts i8 to f64 losslessly.

impl From<i8> for i128[src]

Converts i8 to i128 losslessly.

impl From<i8> for i16[src]

Converts i8 to i16 losslessly.

impl From<i8> for i32[src]

Converts i8 to i32 losslessly.

impl From<i8> for i64[src]

Converts i8 to i64 losslessly.

impl From<i8> for AtomicI8[src]

fn from(v: i8) -> AtomicI8[src]

Converts an i8 into an AtomicI8.

impl From<isize> for AtomicIsize[src]

fn from(v: isize) -> AtomicIsize[src]

Converts an isize into an AtomicIsize.

impl From<!> for Infallible[src]

impl From<!> for TryFromIntError[src]

impl From<u128> for Ipv6Addr[src]

fn from(ip: u128) -> Ipv6Addr[src]

Convert a host byte order u128 into an Ipv6Addr.

Examples

use std::net::Ipv6Addr;

let addr = Ipv6Addr::from(0x102030405060708090A0B0C0D0E0F00D_u128);
assert_eq!(
    Ipv6Addr::new(
        0x1020, 0x3040, 0x5060, 0x7080,
        0x90A0, 0xB0C0, 0xD0E0, 0xF00D,
    ),
    addr);Run

impl From<u16> for usize[src]

Converts u16 to usize losslessly.

impl From<u16> for f32[src]

Converts u16 to f32 losslessly.

impl From<u16> for f64[src]

Converts u16 to f64 losslessly.

impl From<u16> for i128[src]

Converts u16 to i128 losslessly.

impl From<u16> for i32[src]

Converts u16 to i32 losslessly.

impl From<u16> for i64[src]

Converts u16 to i64 losslessly.

impl From<u16> for u128[src]

Converts u16 to u128 losslessly.

impl From<u16> for u32[src]

Converts u16 to u32 losslessly.

impl From<u16> for u64[src]

Converts u16 to u64 losslessly.

impl From<u16> for AtomicU16[src]

fn from(v: u16) -> AtomicU16[src]

Converts an u16 into an AtomicU16.

impl From<u32> for f64[src]

Converts u32 to f64 losslessly.

impl From<u32> for i128[src]

Converts u32 to i128 losslessly.

impl From<u32> for i64[src]

Converts u32 to i64 losslessly.

impl From<u32> for u128[src]

Converts u32 to u128 losslessly.

impl From<u32> for u64[src]

Converts u32 to u64 losslessly.

impl From<u32> for Ipv4Addr[src]

fn from(ip: u32) -> Ipv4Addr[src]

Converts a host byte order u32 into an Ipv4Addr.

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::from(0x0d0c0b0au32);
assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);Run

impl From<u32> for AtomicU32[src]

fn from(v: u32) -> AtomicU32[src]

Converts an u32 into an AtomicU32.

impl From<u64> for i128[src]

Converts u64 to i128 losslessly.

impl From<u64> for u128[src]

Converts u64 to u128 losslessly.

impl From<u64> for AtomicU64[src]

fn from(v: u64) -> AtomicU64[src]

Converts an u64 into an AtomicU64.

impl From<u8> for char[src]

Maps a byte in 0x00..=0xFF to a char whose code point has the same value, in U 0000..=U 00FF.

Unicode is designed such that this effectively decodes bytes with the character encoding that IANA calls ISO-8859-1. This encoding is compatible with ASCII.

Note that this is different from ISO/IEC 8859-1 a.k.a. ISO 8859-1 (with one less hyphen), which leaves some "blanks", byte values that are not assigned to any character. ISO-8859-1 (the IANA one) assigns them to the C0 and C1 control codes.

Note that this is also different from Windows-1252 a.k.a. code page 1252, which is a superset ISO/IEC 8859-1 that assigns some (not all!) blanks to punctuation and various Latin characters.

To confuse things further, on the Web ascii, iso-8859-1, and windows-1252 are all aliases for a superset of Windows-1252 that fills the remaining blanks with corresponding C0 and C1 control codes.

fn from(i: u8) -> char[src]

Converts a u8 into a char.

Examples

use std::mem;

fn main() {
    let u = 32 as u8;
    let c = char::from(u);
    assert!(4 == mem::size_of_val(&c))
}Run

impl From<u8> for usize[src]

Converts u8 to usize losslessly.

impl From<u8> for isize[src]

Converts u8 to isize losslessly.

impl From<u8> for f32[src]

Converts u8 to f32 losslessly.

impl From<u8> for f64[src]

Converts u8 to f64 losslessly.

impl From<u8> for i128[src]

Converts u8 to i128 losslessly.

impl From<u8> for i16[src]

Converts u8 to i16 losslessly.

impl From<u8> for i32[src]

Converts u8 to i32 losslessly.

impl From<u8> for i64[src]

Converts u8 to i64 losslessly.

impl From<u8> for u128[src]

Converts u8 to u128 losslessly.

impl From<u8> for u16[src]

Converts u8 to u16 losslessly.

impl From<u8> for u32[src]

Converts u8 to u32 losslessly.

impl From<u8> for u64[src]

Converts u8 to u64 losslessly.

impl From<u8> for AtomicU8[src]

fn from(v: u8) -> AtomicU8[src]

Converts an u8 into an AtomicU8.

impl From<usize> for AtomicUsize[src]

fn from(v: usize) -> AtomicUsize[src]

Converts an usize into an AtomicUsize.

impl From<LayoutErr> for TryReserveError[src]

impl From<Box<str>> for Box<[u8]>[src]

ⓘImportant traits for Box<I>
fn from(s: Box<str>) -> Box<[u8]>[src]

Converts a Box<str>> into a Box<[u8]>

This conversion does not allocate on the heap and happens in place.

Examples

// create a Box<str> which will be used to create a Box<[u8]>
let boxed: Box<str> = Box::from("hello");
let boxed_str: Box<[u8]> = Box::from(boxed);

// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice = Box::from(slice);

assert_eq!(boxed_slice, boxed_str);Run

impl From<Box<str>> for String[src]

fn from(s: Box<str>) -> String[src]

Converts the given boxed str slice to a String. It is notable that the str slice is owned.

Examples

Basic usage:

let s1: String = String::from("hello world");
let s2: Box<str> = s1.into_boxed_str();
let s3: String = String::from(s2);

assert_eq!("hello world", s3)Run

impl From<Box<CStr>> for CString[src]

fn from(s: Box<CStr>) -> CString[src]

Converts a Box<CStr> into a CString without copying or allocating.

impl From<Box<OsStr>> for OsString[src]

fn from(boxed: Box<OsStr>) -> OsString[src]

Converts a Box<OsStr> into a OsString without copying or allocating.

impl From<Box<Path>> for PathBuf[src]

fn from(boxed: Box<Path>) -> PathBuf[src]

Converts a Box<Path> into a PathBuf

This conversion does not allocate or copy memory.

impl From<CString> for Box<CStr>[src]

ⓘImportant traits for Box<I>
fn from(s: CString) -> Box<CStr>[src]

Converts a CString into a Box<CStr> without copying or allocating.

impl From<CString> for Rc<CStr>[src]

fn from(s: CString) -> Rc<CStr>[src]

Converts a CString into a Rc<CStr> without copying or allocating.

impl From<CString> for Arc<CStr>[src]

fn from(s: CString) -> Arc<CStr>[src]

Converts a CString into a Arc<CStr> without copying or allocating.

impl From<CString> for Vec<u8>[src]

ⓘImportant traits for Vec<u8>
fn from(s: CString) -> Vec<u8>[src]

Converts a CString into a Vec<u8>.

The conversion consumes the CString, and removes the terminating NUL byte.

impl From<NulError> for Error[src]

fn from(_: NulError) -> Error[src]

Converts a NulError into a io::Error.

impl From<OsString> for Box<OsStr>[src]

ⓘImportant traits for Box<I>
fn from(s: OsString) -> Box<OsStr>[src]

Converts a OsString into a Box<OsStr> without copying or allocating.

impl From<OsString> for PathBuf[src]

fn from(s: OsString) -> PathBuf[src]

Converts a OsString into a PathBuf

This conversion does not allocate or copy memory.

impl From<OsString> for Rc<OsStr>[src]

fn from(s: OsString) -> Rc<OsStr>[src]

Converts a OsString into a Rc<OsStr> without copying or allocating.

impl From<OsString> for Arc<OsStr>[src]

fn from(s: OsString) -> Arc<OsStr>[src]

Converts a OsString into a Arc<OsStr> without copying or allocating.

impl From<File> for Stdio[src]

fn from(file: File) -> Stdio[src]

Converts a File into a Stdio

Examples

File will be converted to Stdio using Stdio::from under the hood.

use std::fs::File;
use std::process::Command;

// With the `foo.txt` file containing `Hello, world!"
let file = File::open("foo.txt").unwrap();

let reverse = Command::new("rev")
    .stdin(file)  // Implicit File conversion into a Stdio
    .output()
    .expect("failed reverse command");

assert_eq!(reverse.stdout, b"!dlrow ,olleH");Run

impl From<Ipv4Addr> for IpAddr[src]

impl From<Ipv4Addr> for u32[src]

fn from(ip: Ipv4Addr) -> u32[src]

Converts an Ipv4Addr into a host byte order u32.

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::new(13, 12, 11, 10);
assert_eq!(0x0d0c0b0au32, u32::from(addr));Run

impl From<Ipv6Addr> for IpAddr[src]

impl From<Ipv6Addr> for u128[src]

fn from(ip: Ipv6Addr) -> u128[src]

Convert an Ipv6Addr into a host byte order u128.

Examples

use std::net::Ipv6Addr;

let addr = Ipv6Addr::new(
    0x1020, 0x3040, 0x5060, 0x7080,
    0x90A0, 0xB0C0, 0xD0E0, 0xF00D,
);
assert_eq!(0x102030405060708090A0B0C0D0E0F00D_u128, u128::from(addr));Run

impl From<SocketAddrV4> for SocketAddr[src]

fn from(sock4: SocketAddrV4) -> SocketAddr[src]

Converts a SocketAddrV4 into a SocketAddr::V4.

impl From<SocketAddrV6> for SocketAddr[src]

fn from(sock6: SocketAddrV6) -> SocketAddr[src]

Converts a SocketAddrV6 into a SocketAddr::V6.

impl From<NonZeroI128> for i128[src]

impl From<NonZeroI16> for i16[src]

impl From<NonZeroI32> for i32[src]

impl From<NonZeroI64> for i64[src]

impl From<NonZeroI8> for i8[src]

impl From<NonZeroIsize> for isize[src]

impl From<NonZeroU128> for u128[src]

impl From<NonZeroU16> for u16[src]

impl From<NonZeroU32> for u32[src]

impl From<NonZeroU64> for u64[src]

impl From<NonZeroU8> for u8[src]

impl From<NonZeroUsize> for usize[src]

impl From<PathBuf> for Box<Path>[src]

ⓘImportant traits for Box<I>
fn from(p: PathBuf) -> Box<Path>[src]

Converts a PathBuf into a Box<Path>

This conversion currently should not allocate memory, but this behavior is not guaranteed on all platforms or in all future versions.

impl From<PathBuf> for OsString[src]

fn from(path_buf: PathBuf) -> OsString[src]

Converts a PathBuf into a OsString

This conversion does not allocate or copy memory.

impl From<PathBuf> for Rc<Path>[src]

fn from(s: PathBuf) -> Rc<Path>[src]

Converts a Path into a Rc by copying the Path data into a new Rc buffer.

impl From<PathBuf> for Arc<Path>[src]

fn from(s: PathBuf) -> Arc<Path>[src]

Converts a Path into a Rc by copying the Path data into a new Rc buffer.

impl From<ChildStderr> for Stdio[src]

fn from(child: ChildStderr) -> Stdio[src]

Converts a ChildStderr into a Stdio

Examples

use std::process::{Command, Stdio};

let reverse = Command::new("rev")
    .arg("non_existing_file.txt")
    .stderr(Stdio::piped())
    .spawn()
    .expect("failed reverse command");

let cat = Command::new("cat")
    .arg("-")
    .stdin(reverse.stderr.unwrap()) // Converted into a Stdio here
    .output()
    .expect("failed echo command");

assert_eq!(
    String::from_utf8_lossy(&cat.stdout),
    "rev: cannot open non_existing_file.txt: No such file or directory\n"
);Run

impl From<ChildStdin> for Stdio[src]

fn from(child: ChildStdin) -> Stdio[src]

Converts a ChildStdin into a Stdio

Examples

ChildStdin will be converted to Stdio using Stdio::from under the hood.

use std::process::{Command, Stdio};

let reverse = Command::new("rev")
    .stdin(Stdio::piped())
    .spawn()
    .expect("failed reverse command");

let _echo = Command::new("echo")
    .arg("Hello, world!")
    .stdout(reverse.stdin.unwrap()) // Converted into a Stdio here
    .output()
    .expect("failed echo command");

// "!dlrow ,olleH" echoed to consoleRun

impl From<ChildStdout> for Stdio[src]

fn from(child: ChildStdout) -> Stdio[src]

Converts a ChildStdout into a Stdio

Examples

ChildStdout will be converted to Stdio using Stdio::from under the hood.

use std::process::{Command, Stdio};

let hello = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::piped())
    .spawn()
    .expect("failed echo command");

let reverse = Command::new("rev")
    .stdin(hello.stdout.unwrap())  // Converted into a Stdio here
    .output()
    .expect("failed reverse command");

assert_eq!(reverse.stdout, b"!dlrow ,olleH\n");Run

impl From<String> for Box<str>[src]

ⓘImportant traits for Box<I>
fn from(s: String) -> Box<str>[src]

Converts the given String to a boxed str slice that is owned.

Examples

Basic usage:

let s1: String = String::from("hello world");
let s2: Box<str> = Box::from(s1);
let s3: String = String::from(s2);

assert_eq!("hello world", s3)Run

impl From<String> for Box<dyn Error Send Sync>[src]

ⓘImportant traits for Box<I>
fn from(err: String) -> Box<dyn Error Send Sync>[src]

Converts a String into a box of dyn Error trait@Send trait@Sync.

Examples

use std::error::Error;
use std::mem;

let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<dyn Error   Send   Sync>::from(a_string_error);
assert!(
    mem::size_of::<Box<dyn Error   Send   Sync>>() == mem::size_of_val(&a_boxed_error))Run

impl From<String> for Box<dyn Error>[src]

ⓘImportant traits for Box<I>
fn from(str_err: String) -> Box<dyn Error>[src]

Converts a String into a box of dyn Error.

Examples

use std::error::Error;
use std::mem;

let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<dyn Error>::from(a_string_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))Run

impl From<String> for OsString[src]

fn from(s: String) -> OsString[src]

Converts a String into a OsString.

The conversion copies the data, and includes an allocation on the heap.

impl From<String> for PathBuf[src]

fn from(s: String) -> PathBuf[src]

Converts a String into a PathBuf

This conversion does not allocate or copy memory.

impl From<String> for Rc<str>[src]

impl From<String> for Arc<str>[src]

impl From<String> for Vec<u8>[src]

ⓘImportant traits for Vec<u8>
fn from(string: String) -> Vec<u8>[src]

Converts the given String to a vector Vec that holds values of type u8.

Examples

Basic usage:

let s1 = String::from("hello world");
let v1 = Vec::from(s1);

for b in v1 {
    println!("{}", b);
}Run

impl From<RecvError> for RecvTimeoutError[src]

impl From<RecvError> for TryRecvError[src]

' class='impl'>impl<'_> From<&'_ str> for Box<str>[src]

ⓘImportant traits for Box<I>
fn from(s: &str) -> Box<str>[src]

Converts a &str into a Box<str>

This conversion allocates on the heap and performs a copy of s.

Examples

let boxed: Box<str> = Box::from("hello");
println!("{}", boxed);Run

-1' class='impl'>impl<'_> From<&'_ str> for Box<dyn Error>[src]

ⓘImportant traits for Box<I>
fn from(err: &str) -> Box<dyn Error>[src]

Converts a str into a box of dyn Error.

Examples

use std::error::Error;
use std::mem;

let a_str_error = "a str error";
let a_boxed_error = Box::<dyn Error>::from(a_str_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))Run

-2' class='impl'>impl<'_> From<&'_ str> for Rc<str>[src]

-3' class='impl'>impl<'_> From<&'_ str> for String[src]

-4' class='impl'>impl<'_> From<&'_ str> for Arc<str>[src]

-5' class='impl'>impl<'_> From<&'_ str> for Vec<u8>[src]

' class='impl'>impl<'_> From<&'_ CStr> for Box<CStr>[src]

-1' class='impl'>impl<'_> From<&'_ CStr> for CString[src]

-2' class='impl'>impl<'_> From<&'_ CStr> for Rc<CStr>[src]

-3' class='impl'>impl<'_> From<&'_ CStr> for Arc<CStr>[src]

' class='impl'>impl<'_> From<&'_ OsStr> for Box<OsStr>[src]

-1' class='impl'>impl<'_> From<&'_ OsStr> for Rc<OsStr>[src]

-2' class='impl'>impl<'_> From<&'_ OsStr> for Arc<OsStr>[src]

' class='impl'>impl<'_> From<&'_ Path> for Box<Path>[src]

-1' class='impl'>impl<'_> From<&'_ Path> for Rc<Path>[src]

fn from(s: &Path) -> Rc<Path>[src]

Converts a Path into a Rc by copying the Path data into a new Rc buffer.

-2' class='impl'>impl<'_> From<&'_ Path> for Arc<Path>[src]

fn from(s: &Path) -> Arc<Path>[src]

Converts a Path into a Rc by copying the Path data into a new Rc buffer.

' class='impl'>impl<'_> From<&'_ String> for String[src]

' class='impl'>impl<'_, T> From<&'_ T> for NonNull<T> where
    T: ?Sized, [src]

' class='impl'>impl<'_, T> From<&'_ mut T> for NonNull<T> where
    T: ?Sized, [src]

' class='impl'>impl<'_, T> From<&'_ [T]> for Box<[T]> where
    T: Copy, [src]

ⓘImportant traits for Box<I>
fn from(slice: &[T]) -> Box<[T]>[src]

Converts a &[T] into a Box<[T]>

This conversion allocates on the heap and performs a copy of slice.

Examples

// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice: Box<[u8]> = Box::from(slice);

println!("{:?}", boxed_slice);Run

-1' class='impl'>impl<'_, T> From<&'_ [T]> for Rc<[T]> where
    T: Clone, [src]

-2' class='impl'>impl<'_, T> From<&'_ [T]> for Arc<[T]> where
    T: Clone, [src]

-3' class='impl'>impl<'_, T> From<&'_ [T]> for Vec<T> where
    T: Clone, [src]

' class='impl'>impl<'_, T> From<&'_ mut [T]> for Vec<T> where
    T: Clone, [src]

-1' class='impl'>impl<'_, T: ?Sized AsRef<OsStr>> From<&'_ T> for OsString[src]

-2' class='impl'>impl<'_, T: ?Sized AsRef<OsStr>> From<&'_ T> for PathBuf[src]

' class='impl'>impl<'a> From<&'a str> for Cow<'a, str>[src]

' class='impl'>impl<'a> From<&'a CStr> for Cow<'a, CStr>[src]

' class='impl'>impl<'a> From<&'a CString> for Cow<'a, CStr>[src]

' class='impl'>impl<'a> From<&'a OsStr> for Cow<'a, OsStr>[src]

' class='impl'>impl<'a> From<&'a OsString> for Cow<'a, OsStr>[src]

' class='impl'>impl<'a> From<&'a Path> for Cow<'a, Path>[src]

' class='impl'>impl<'a> From<&'a PathBuf> for Cow<'a, Path>[src]

' class='impl'>impl<'a> From<&'a String> for Cow<'a, str>[src]

>' class='impl'>impl<'a> From<Cow<'a, str>> for Box<dyn Error>[src]

ⓘImportant traits for Box<I>
fn from(err: Cow<'a, str>) -> Box<dyn Error>[src]

Converts a Cow into a box of dyn Error.

Examples

use std::error::Error;
use std::mem;
use std::borrow::Cow;

let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error>::from(a_cow_str_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))Run

>-1' class='impl'>impl<'a> From<Cow<'a, str>> for String[src]

>' class='impl'>impl<'a> From<Cow<'a, CStr>> for CString[src]

>' class='impl'>impl<'a> From<Cow<'a, OsStr>> for OsString[src]

>' class='impl'>impl<'a> From<Cow<'a, Path>> for PathBuf[src]

impl<'a> From<CString> for Cow<'a, CStr>[src]

impl<'a> From<OsString> for Cow<'a, OsStr>[src]

impl<'a> From<PathBuf> for Cow<'a, Path>[src]

impl<'a> From<String> for Cow<'a, str>[src]

-6' class='impl'>impl<'a, '_> From<&'_ str> for Box<dyn Error Send Sync 'a>[src]

ⓘImportant traits for Box<I>
fn from(err: &str) -> Box<dyn Error Send Sync 'a>[src]

Converts a str into a box of dyn Error trait@Send trait@Sync.

Examples

use std::error::Error;
use std::mem;

let a_str_error = "a str error";
let a_boxed_error = Box::<dyn Error   Send   Sync>::from(a_str_error);
assert!(
    mem::size_of::<Box<dyn Error   Send   Sync>>() == mem::size_of_val(&a_boxed_error))Run

>' class='impl'>impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error Send Sync 'a>[src]

ⓘImportant traits for Box<I>
fn from(err: Cow<'b, str>) -> Box<dyn Error Send Sync 'a>[src]

Converts a Cow into a box of dyn Error trait@Send trait@Sync.

Examples

use std::error::Error;
use std::mem;
use std::borrow::Cow;

let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error   Send   Sync>::from(a_cow_str_error);
assert!(
    mem::size_of::<Box<dyn Error   Send   Sync>>() == mem::size_of_val(&a_boxed_error))Run

impl<'a, E: Error 'a> From<E> for Box<dyn Error 'a>[src]

ⓘImportant traits for Box<I>
fn from(err: E) -> Box<dyn Error 'a>[src]

Converts a type of Error into a box of dyn Error.

Examples

use std::error::Error;
use std::fmt;
use std::mem;

#[derive(Debug)]
struct AnError;

impl fmt::Display for AnError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f , "An error")
    }
}

impl Error for AnError {
    fn description(&self) -> &str {
        "Description of an error"
    }
}

let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error>::from(an_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))Run

impl<'a, E: Error Send Sync 'a> From<E> for Box<dyn Error Send Sync 'a>[src]

ⓘImportant traits for Box<I>
fn from(err: E) -> Box<dyn Error Send Sync 'a>[src]

Converts a type of Error trait@Send trait@Sync into a box of dyn Error trait@Send trait@Sync.

Examples

use std::error::Error;
use std::fmt;
use std::mem;

#[derive(Debug)]
struct AnError;

impl fmt::Display for AnError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f , "An error")
    }
}

impl Error for AnError {
    fn description(&self) -> &str {
        "Description of an error"
    }
}

unsafe impl Send for AnError {}

unsafe impl Sync for AnError {}

let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error   Send   Sync>::from(an_error);
assert!(
    mem::size_of::<Box<dyn Error   Send   Sync>>() == mem::size_of_val(&a_boxed_error))Run

>' class='impl'>impl<'a, T> From<&'a Option<T>> for Option<&'a T>[src]

>' class='impl'>impl<'a, T> From<&'a Vec<T>> for Cow<'a, [T]> where
    T: Clone, [src]

>' class='impl'>impl<'a, T> From<&'a mut Option<T>> for Option<&'a mut T>[src]

>' class='impl'>impl<'a, T> From<Cow<'a, [T]>> for Vec<T> where
    [T]: ToOwned,
    <[T] as ToOwned>::Owned == Vec<T>, [src]

' class='impl'>impl<'a, T> From<&'a [T]> for Cow<'a, [T]> where
    T: Clone, [src]

impl<'a, T> From<Vec<T>> for Cow<'a, [T]> where
    T: Clone, [src]

impl<I: Into<IpAddr>> From<(I, u16)> for SocketAddr[src]

fn from(pieces: (I, u16)) -> SocketAddr[src]

Converts a tuple struct (Into<IpAddr>, u16) into a SocketAddr.

This conversion creates a SocketAddr::V4 for a IpAddr::V4 and creates a SocketAddr::V6 for a IpAddr::V6.

u16 is treated as port of the newly created SocketAddr.

impl<T> From<*mut T> for AtomicPtr<T>[src]

impl<T> From<Box<[T]>> for Vec<T>[src]

impl<T> From<Box<T>> for Pin<Box<T>> where
    T: ?Sized, [src]

ⓘImportant traits for Pin<P>
fn from(boxed: Box<T>) -> Pin<Box<T>>[src]

Converts a Box<T> into a Pin<Box<T>>

This conversion does not allocate on the heap and happens in place.

impl<T> From<Box<T>> for Rc<T> where
    T: ?Sized, [src]

impl<T> From<Box<T>> for Arc<T> where
    T: ?Sized, [src]

impl<T> From<BinaryHeap<T>> for Vec<T>[src]

impl<T> From<VecDeque<T>> for Vec<T>[src]

ⓘImportant traits for Vec<u8>
fn from(other: VecDeque<T>) -> Vec<T>[src]

Turn a VecDeque<T> into a Vec<T>.

This never needs to re-allocate, but does need to do O(n) data movement if the circular buffer doesn't happen to be at the beginning of the allocation.

Examples

use std::collections::VecDeque;

// This one is O(1).
let deque: VecDeque<_> = (1..5).collect();
let ptr = deque.as_slices().0.as_ptr();
let vec = Vec::from(deque);
assert_eq!(vec, [1, 2, 3, 4]);
assert_eq!(vec.as_ptr(), ptr);

// This one needs data rearranging.
let mut deque: VecDeque<_> = (1..5).collect();
deque.push_front(9);
deque.push_front(8);
let ptr = deque.as_slices().1.as_ptr();
let vec = Vec::from(deque);
assert_eq!(vec, [8, 9, 1, 2, 3, 4]);
assert_eq!(vec.as_ptr(), ptr);Run

impl<T> From<SendError<T>> for TrySendError<T>[src]

impl<T> From<PoisonError<T>> for TryLockError<T>[src]

impl<T> From<Vec<T>> for Box<[T]>[src]

impl<T> From<Vec<T>> for BinaryHeap<T> where
    T: Ord, [src]

fn from(vec: Vec<T>) -> BinaryHeap<T>[src]

Converts a Vec<T> into a BinaryHeap<T>.

This conversion happens in-place, and has O(n) time complexity.

impl<T> From<Vec<T>> for VecDeque<T>[src]

fn from(other: Vec<T>) -> VecDeque<T>[src]

Turn a Vec<T> into a VecDeque<T>.

This avoids reallocating where possible, but the conditions for that are strict, and subject to change, and so shouldn't be relied upon unless the Vec<T> came from From<VecDeque<T>> and hasn't been reallocated.

impl<T> From<Vec<T>> for Rc<[T]>[src]

impl<T> From<Vec<T>> for Arc<[T]>[src]

impl<T> From<T> for Option<T>[src]

impl<T> From<T> for Poll<T>[src]

impl<T> From<T> for Box<T>[src]

ⓘImportant traits for Box<I>
fn from(t: T) -> Box<T>[src]

Converts a generic type T into a Box<T>

The conversion allocates on the heap and moves t from the stack into it.

Examples

let x = 5;
let boxed = Box::new(5);

assert_eq!(Box::from(x), boxed);Run

impl<T> From<T> for Cell<T>[src]

impl<T> From<T> for RefCell<T>[src]

impl<T> From<T> for UnsafeCell<T>[src]

impl<T> From<T> for Rc<T>[src]

impl<T> From<T> for Arc<T>[src]

impl<T> From<T> for Mutex<T>[src]

fn from(t: T) -> Self[src]

Creates a new mutex in an unlocked state ready for use. This is equivalent to Mutex::new.

impl<T> From<T> for RwLock<T>[src]

fn from(t: T) -> Self[src]

Creates a new instance of an RwLock<T> which is unlocked. This is equivalent to RwLock::new.

impl<T> From<T> for T[src]

impl<T> From<Unique<T>> for NonNull<T> where
    T: ?Sized, [src]

impl<W> From<IntoInnerError<W>> for Error[src]

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