Trait Display

1.0.0 · Source

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.

§Internationalization

Because a type can only have one Display implementation, it is often preferable to only implement Display when there is a single most “obvious” way that values can be formatted as text. This could mean formatting according to the “invariant” culture and “undefined” locale, or it could mean that the type display is designed for a specific culture/locale, such as developer logs.

If not all values have a justifiably canonical textual format or if you want to support alternative formats not covered by the standard set of possible formatting traits, the most flexible approach is display adapters: methods like str::escape_default or Path::display which create a wrapper implementing Display to output the specific display format.

§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)");

Required Methods§

1.0.0 · Source

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

Formats the value using the given formatter.

§Errors

This function should return Err if, and only if, the provided Formatter returns Err. String formatting is considered an infallible operation; this function only returns a Result because writing to the underlying stream might fail and it must provide a way to propagate the fact that an error has occurred back up the stack.

§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, }),
);

Trait DisplayCopy item path

§Internationalization

§Examples

Required Methods§

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

§Errors

§Examples

Implementors§

impl Display for rstsr_core::error::Error

impl Display for AsciiChar

impl Display for Infallible

impl Display for FromBytesWithNulError

impl Display for IpAddr

impl Display for SocketAddr

impl Display for GetManyMutError

impl Display for VarError

impl Display for ErrorKind

impl Display for RecvTimeoutError

impl Display for TryRecvError

impl Display for CheckedCastError

impl Display for PodCastError

impl Display for CreationError

impl Display for FaerError

impl Display for faer::sparse::linalg::CholeskyError

impl Display for LuError

impl Display for Entry

impl Display for Endianness

impl Display for TimeUnits

impl Display for TypeChar

impl Display for Value

impl Display for FormatError

impl Display for py_literal::parse::ParseError

impl Display for BernoulliError

impl Display for rand_distr::binomial::Error

impl Display for rand_distr::cauchy::Error

impl Display for rand_distr::exponential::Error

impl Display for rand_distr::frechet::Error

impl Display for BetaError

impl Display for ChiSquaredError

impl Display for rand_distr::gamma::Error

impl Display for FisherFError

impl Display for rand_distr::geometric::Error

impl Display for rand_distr::gumbel::Error

impl Display for rand_distr::hypergeometric::Error

impl Display for rand_distr::inverse_gaussian::Error

impl Display for rand_distr::normal::Error

impl Display for rand_distr::normal_inverse_gaussian::Error

impl Display for rand_distr::pareto::Error

impl Display for PertError

impl Display for rand_distr::poisson::Error

impl Display for rand_distr::skew_normal::Error

impl Display for TriangularError

impl Display for rand_distr::weibull::Error

impl Display for ZetaError

impl Display for ZipfError

impl Display for CacheType

impl Display for DatType

impl Display for ExtendedRegisterStateLocation

impl Display for ExtendedRegisterType

impl Display for TopologyType

impl Display for Associativity

impl Display for ucd_trie::owned::Error

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

Trait Display