Module std::fmt

String formatting

The core of the formatting system is the Formattable protocol. Implementing it on custom types allows them to be formatted using the standard string-formatting macros (format, write, ...) and the convenience standard I/O macros (print, println, ...).

Protocols

Structs

Functions

• fn hex<T>(val: T) -> NumFormatAdapter<T>

  T: Integer

  source

  Write value as a hexadecimal number

  Example

  use std::fmt::hex;
  
  println!("{}", 42.hex()); // prints '2a'
  Run this example

• fn bin<T>(val: T) -> NumFormatAdapter<T>

  T: Integer

  source

  Write value as a binary number

  Example

  use std::fmt::bin;
  
  println!("{}", 42.bin()); // prints '101010'
  Run this example

• fn oct<T>(val: T) -> NumFormatAdapter<T>

  T: Integer

  source

  Write value as an octal number

  Example

  use std::fmt::oct;
  
  println!("{}", 42.oct()); // prints '52'
  Run this example

• fn zero_pad<T>(val: T, pad: usize) -> NumFormatAdapter<T>

  T: Integer

  source

  Pads number with zeros on the left.

  Example

  use std::fmt::zero_pad;
  
  println!("{}", 42.zero_pad(5)); // prints '00042'
  Run this example

• fn precision<T>(val: T, prec: u16) -> FloatFormatAdapter<T>

  T: FloatingPoint

  source

• fn repeat<T>(inner: T, times: usize) -> RepeatAdapter<T>

  T: Formattable<T>

  source

  Repeats value times times.

  Example

  use std::fmt::repeat;
  
  println!("{}", "ha".repeat(3)); // prints 'hahaha'
  Run this example

• fn pad_with<T>(val: T, len: usize, pad: u8) -> GenericPadAdapter<T>

  T: Formattable<T>

  source

  Pads arbitrary formattable value on the left with a specified character.

  Example

  use std::fmt::pad_with;
  
  println!("{}", "ha".pad_with(5, ' ')); // prints '   ha'
  Run this example

• fn char(val: u8) -> CharAdapter

  source

  Writes a single u8 as a character (byte).

  By default, u8 is written as a number.

  Example

  use std::fmt::char;
  
  println!("{}", 'A'); // prints '65'
  println!("{}", 'A'.char()); // prints 'A'
  Run this example

Types

• type Result = Result<(), Error>

  source

Macros