How do I add days to a Chrono UTC?

Question

I am trying to find the preferred way to add days to a Chrono UTC. I want to add 137 days to the current time:

let dt = UTC::now();

Stargateur · Accepted Answer · 2021-06-16T14:51:45.270

85

Just use Duration and appropriate operator:

use chrono::{Duration, Utc};

fn main() {
    let dt = Utc::now() + Duration::days(137);

    println!("today date + 137 days {}", dt);
}

edited Jun 16 '21 at 14:51

answered Jun 22 '17 at 23:41

Stargateur

7

Thank you, i missed the arithmetic part. Great community, great crates. The documentation format tho feels like I am reading MSDN. Thanks for the correct easy answer, a lot better than what i was doing after reading through those docs for the 11th time :-) – schmoopy Jun 22 '17 at 23:44
Wow! This is much better than momentJS – Gus Jun 22 '22 at 19:19
It's worth noting that the "+ Duration" function is implemented for DateTime<_>, but the reverse is NOT true, so while ```Utc::now() + Duration::days(137)``` works the reverse does not: ```Duration::days(137) + Utc::now()``` – capveg Aug 29 '23 at 16:13

score 45 · Answer 2 · answered Apr 12 '18 at 07:38

45

I just wanted to improve on @Stargateur answer. There is no need to use time crate, since chrono crate has Duration struct in it:

extern crate chrono;

use chrono::{Duration, Utc};

fn main() {
    let dt = Utc::now() + Duration::days(137);

    println!("{}", dt);
}

answered Apr 12 '18 at 07:38

Yerke

1

Note that currently `Duration` is just a wrapper to `time::Duration`, there could be breaking change by using `Duration` directly – Stargateur Apr 12 '18 at 08:45
11

@Stargateur If there was a breaking change between chrono and time crates, I'd think that using the, using chrono's `Duration` lets me rely on the chrono crate to fix the problem, so I can just update that one dependency without having to make a code change myself. – Peter Hall Apr 12 '18 at 14:49
2

As of May/2020, using `chrono::Duration` is actually necessary, since `time::Duration` doesn't implement the addition trait. – Marcus May 14 '20 at 20:54

2 Answers2