Rust:
Converting a date into a string

How to:

Rust’s chrono crate is the go-to for date and time handling. Make sure it’s in your Cargo.toml:

[dependencies]
chrono = "0.4"

Now, let’s format a date as a string.

extern crate chrono;
use chrono::{DateTime, Utc, NaiveDateTime};

fn main() {
    let date: DateTime<Utc> = Utc::now(); // Get current UTC date and time.
    let formatted_date = date.format("%Y-%m-%d %H:%M:%S").to_string();
    println!("{}", formatted_date); // Prints: 2023-03-15 14:30:45
}

Deep Dive

Before chrono, Rust’s standard library had a few date and time functions, but they were basic. chrono built on that bedrock to offer comprehensive functionality. An alternative might be Rust’s new time crate, aiming for a safer and more ergonomic API.

When you convert a date to a string, you’re serializing – turning data into a format that can be shared or stored. The format you choose (%Y-%m-%d %H:%M:%S in our case) is up to you, and chrono supports many such patterns.

Internally, dates are often stored as timestamps – seconds from a starting point, like Unix epoch (January 1, 1970). When you format a date, you compute the human-readable form from this count, considering time zones and leap seconds.

See Also

• chrono crate documentation: https://docs.rs/chrono/
• Rust’s time crate documentation: https://docs.rs/time/
• Date formatting syntax: http://www.unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table