UpperExp in alloc::fmt - Rust
Description: `E` formatting.
Keywords: rust, rustlang, rust-lang, UpperExp

# Trait alloc::fmt::UpperExp
1.0.0[−][src]

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

Expand description

`E` formatting.

The `UpperExp` trait should format its output in scientific notation with an upper-case `E`.

For more information on formatters, see the module-level documentation.

# Examples

Basic usage with `f64`:

    let x = 42.0; // 42.0 is '4.2E1' in scientific notation

    assert_eq!(format!("{:E}", x), "4.2E1");

Run

Implementing `UpperExp` on a type:

    use std::fmt;

    struct Length(i32);

    impl fmt::UpperExp for Length {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            let val = f64::from(self.0);
            fmt::UpperExp::fmt(&val, f) // delegate to f64's implementation
        }
    }

    let l = Length(100);

    assert_eq!(
        format!("l in scientific notation is: {:E}", l),
        "l in scientific notation is: 1E2"
    );

    assert_eq!(
        format!("l in scientific notation is: {:05E}", l),
        "l in scientific notation is: 001E2"
    );

Run

## Required methods

[src]

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

Formats the value using the given formatter.

## Implementors

[src]

### impl UpperExp for f32

[src]

### impl UpperExp for f64

1.42.0[src]

### impl UpperExp for i8

1.42.0[src]

### impl UpperExp for i16

1.42.0[src]

### impl UpperExp for i32

1.42.0[src]

### impl UpperExp for i64

1.42.0[src]

### impl UpperExp for i128

1.42.0[src]

### impl UpperExp for isize

1.42.0[src]

### impl UpperExp for u8

1.42.0[src]

### impl UpperExp for u16

1.42.0[src]

### impl UpperExp for u32

1.42.0[src]

### impl UpperExp for u64

1.42.0[src]

### impl UpperExp for u128

1.42.0[src]

### impl UpperExp for usize

[src]

### impl<'_, T> UpperExp for &'_ T where
T: UpperExp + ?Sized,

[src]

### impl<'_, T> UpperExp for &'_ mut T where
T: UpperExp + ?Sized,