pub trait Display {
// Required method
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}
Expand description
Format trait for an empty format, {}
.
Implementing this trait for a type will automatically implement the
ToString
trait for the type, allowing the usage
of the .to_string()
method. Prefer implementing
the Display
trait for a type, rather than ToString
.
Display
is similar to Debug
, but Display
is for user-facing
output, and so cannot be derived.
For more information on formatters, see the module-level documentation.
Examples
Implementing Display
on a type:
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)");
RunRequired Methods§
sourcefn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter.
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, }));
RunImplementors§
impl Display for AsciiChar
impl Display for Infallible
impl Display for IpAddr
impl Display for SocketAddr
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 TryFromSliceError
impl Display for core::ascii::EscapeDefault
impl Display for BorrowError
impl Display for BorrowMutError
impl Display for CharTryFromError
impl Display for ParseCharError
impl Display for DecodeUtf16Error
impl Display for core::char::EscapeDebug
impl Display for core::char::EscapeDefault
impl Display for core::char::EscapeUnicode
impl Display for ToLowercase
impl Display for ToUppercase
impl Display for TryFromCharError
impl Display for FromBytesUntilNulError
impl Display for FromBytesWithNulError
impl Display for Ipv4Addr
impl Display for Ipv6Addr
Write an Ipv6Addr, conforming to the canonical style described by RFC 5952.