CODEWITHSUNDEEP
stringparsingserializationrustnumbers
mazznoer
mazznoer

Reputation: 113

How to convert f64 into String and parse back into f64?

let s = format!("{}", t);
let x = s.parse::<f64>();

If t is of type f64, is there any case that the parsing back to f64 would fail?

Upvotes: 3

Views: 2912

Answers (1)

pretzelhammer
pretzelhammer

Reputation: 15135

Doesn't seem so. This program covers all interesting edge cases, e.g. NaN, Infinity, Negative Infinity, etc, and it compiles and runs fine without panicking:

fn check_serialization_eq(nums: &[f64]) {
    for num in nums {
        let s = num.to_string();
        let x = s.parse::<f64>().unwrap();
        dbg!(num, x);
    }
}

fn main() {
    check_serialization_eq(&[
        f64::MIN,
        f64::MAX,
        f64::NAN,
        f64::INFINITY,
        f64::NEG_INFINITY,
        f64::EPSILON,
    ]);
}

playground

Upvotes: 3

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