如何在Rust中解码和编码浮点数？ [英] How to decode and encode a float in Rust?

问题描述

我想在Rust中解码，存储和编码一个浮点数。我知道 num :: Float :: integer_decode（） ，但我宁愿不会失去任何精度。也就是说，除非我编码的格式小于我当然编码的格式。 解释方法解释浮点数作为一个整数，打印出十六进制的值：

  use std :: mem; 
 
 fn main（）{
 let a_third：f64 = 1.0 / 3.0; 
 
 let as_int：u64 = unsafe {mem :: transmute（a_third）}; 
 println！（{}，as_int）; 
 
 let as_string = format！（{：016x}，as_int）; 
 println！（{}，as_string）; 
 
 let back_to_int = u64 :: from_str_radix（& as_string，16）.expect（Not an integer）; 
 println！（{}，back_to_int）; 
 
 let back_to_float：f64 = unsafe {mem :: transmute（back_to_int）}; 
 println！（{}，back_to_float）; 
 
 assert_eq！（back_to_float，a_third）; 
} 
  

I want to decode, store and encode a float in Rust. I know about num::Float::integer_decode() but I'd rather not lose any precision. That is, unless the format I encode into is smaller than the format I encode from of course.

解决方案

Interpret the floating point bits as an integer and print out the value as hex:

use std::mem;

fn main() {
    let a_third: f64 = 1.0 / 3.0;

    let as_int: u64 = unsafe { mem::transmute(a_third) };
    println!("{}", as_int);

    let as_string = format!("{:016x}", as_int);
    println!("{}", as_string);

    let back_to_int = u64::from_str_radix(&as_string, 16).expect("Not an integer");
    println!("{}", back_to_int);

    let back_to_float: f64 = unsafe { mem::transmute(back_to_int) };
    println!("{}", back_to_float);

    assert_eq!(back_to_float, a_third);
}

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