Trait frame_support::dispatch::fmt::LowerExp 1.0.0[−][src]
Expand description
e
formatting.
The LowerExp
trait should format its output in scientific notation with a lower-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");
Implementing LowerExp
on a type:
use std::fmt; struct Length(i32); impl fmt::LowerExp for Length { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { let val = f64::from(self.0); fmt::LowerExp::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" );