Trait std::fmt::Display

pub trait Display {
    // Required method
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}

空格式的格式 trait，{}。

为一个类型实现这个 trait 将自动为该类型实现 ToString trait，允许使用 .to_string() 方法。 更喜欢为一个类型实现 Display trait，而不是 ToString。

Display 与 Debug 类似，但 Display 是面向用户的输出，因此无法导出。

有关格式化程序的更多信息，请参见 模块级文档。

Examples

在类型上实现 Display：

use std::fmt;

struct Point {
    x: i32,
    y: i32,
}

impl fmt::Display for Point {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "({}, {})", self.x, self.y)
    }
}

let origin = Point { x: 0, y: 0 };

assert_eq!(format!("The origin is: {origin}"), "The origin is: (0, 0)");

Required Methods

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

使用给定的格式化程序格式化该值。

Examples

use std::fmt;

struct Position {
    longitude: f32,
    latitude: f32,
}

impl fmt::Display for Position {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "({}, {})", self.longitude, self.latitude)
    }
}

assert_eq!("(1.987, 2.983)",
           format!("{}", Position { longitude: 1.987, latitude: 2.983, }));

Implementors

impl Display for AsciiChar

impl Display for Infallible

impl Display for VarError

impl Display for ErrorKind

impl Display for IpAddr

impl Display for SocketAddr

impl Display for RecvTimeoutError

impl Display for TryRecvError

impl Display for bool

impl Display for char

impl Display for f32

impl Display for f64

impl Display for i8

impl Display for i16

impl Display for i32

impl Display for i64

impl Display for i128

impl Display for isize

impl Display for !

impl Display for str

impl Display for u8

impl Display for u16

impl Display for u32

impl Display for u64

impl Display for u128

impl Display for usize

impl Display for FromBytesUntilNulError

impl Display for AllocError

impl Display for LayoutError

impl Display for TryFromSliceError

impl Display for std::ascii::EscapeDefault

impl Display for Backtrace

impl Display for BorrowError

impl Display for BorrowMutError

impl Display for CharTryFromError

impl Display for DecodeUtf16Error

impl Display for std::char::EscapeDebug

impl Display for std::char::EscapeDefault

impl Display for std::char::EscapeUnicode

impl Display for ParseCharError

impl Display for ToLowercase

impl Display for ToUppercase

impl Display for TryFromCharError

impl Display for TryReserveError

impl Display for JoinPathsError

impl Display for FromBytesWithNulError

impl Display for FromVecWithNulError

impl Display for IntoStringError

impl Display for NulError

impl Display for std::io::Error

impl Display for WriterPanicked

impl Display for AddrParseError

impl Display for Ipv4Addr

impl Display for Ipv6Addr

编写一个符合 RFC 5952 描述的规范样式的 Ivv6Addr。

impl Display for SocketAddrV4

impl Display for SocketAddrV6

impl Display for NonZeroI8

impl Display for NonZeroI16

impl Display for NonZeroI32

impl Display for NonZeroI64

impl Display for NonZeroI128

impl Display for NonZeroIsize

impl Display for NonZeroU8

impl Display for NonZeroU16

impl Display for NonZeroU32

impl Display for NonZeroU64

impl Display for NonZeroU128

impl Display for NonZeroUsize

impl Display for ParseFloatError

impl Display for ParseIntError

impl Display for TryFromIntError

impl Display for InvalidHandleError

Available on Windows only.

impl Display for NullHandleError

Available on Windows only.

impl Display for Location<'_>

impl Display for PanicInfo<'_>

impl Display for Display<'_>

impl Display for StripPrefixError

impl Display for ExitStatus

impl Display for ExitStatusError

impl Display for ParseBoolError

impl Display for Utf8Error

impl Display for FromUtf8Error

impl Display for FromUtf16Error

impl Display for String

impl Display for RecvError

impl Display for AccessError

impl Display for SystemTimeError

impl Display for TryFromFloatSecsError

impl Display for Arguments<'_>

impl Display for std::fmt::Error

impl<'a> Display for EscapeAscii<'a>

impl<'a> Display for std::str::EscapeDebug<'a>

impl<'a> Display for std::str::EscapeDefault<'a>

impl<'a> Display for std::str::EscapeUnicode<'a>

impl<'a, K, V, A> Display for std::collections::btree_map::OccupiedError<'a, K, V, A>where K: Debug + Ord, V: Debug, A: Allocator + Clone,

impl<'a, K: Debug, V: Debug> Display for std::collections::hash_map::OccupiedError<'a, K, V>

impl<B> Display for Cow<'_, B>where B: Display + ToOwned + ?Sized, <B as ToOwned>::Owned: Display,

impl<E> Display for Report<E>where E: Error,

impl<P> Display for Pin<P>where P: Display,

impl<T> Display for TryLockError<T>

impl<T> Display for TrySendError<T>

impl<T> Display for &Twhere T: Display + ?Sized,

impl<T> Display for &mut Twhere T: Display + ?Sized,

impl<T> Display for ThinBox<T>where T: Display + ?Sized,

impl<T> Display for Ref<'_, T>where T: Display + ?Sized,

impl<T> Display for RefMut<'_, T>where T: Display + ?Sized,

impl<T> Display for Saturating<T>where T: Display,

impl<T> Display for Wrapping<T>where T: Display,

impl<T> Display for Rc<T>where T: Display + ?Sized,

impl<T> Display for SendError<T>

impl<T> Display for Arc<T>where T: Display + ?Sized,

impl<T> Display for PoisonError<T>

impl<T, A> Display for Box<T, A>where T: Display + ?Sized, A: Allocator,

impl<T: ?Sized + Display> Display for MutexGuard<'_, T>

impl<T: ?Sized + Display> Display for RwLockReadGuard<'_, T>

impl<T: ?Sized + Display> Display for RwLockWriteGuard<'_, T>

impl<W> Display for IntoInnerError<W>

impl<const N: usize> Display for GetManyMutError<N>