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Adds "converting a local time to UTC time and vice versa" recipe

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Lenard Pratt 2017-11-15 13:59:00 +00:00 • committed by Michał Budzyński
parent eec1522d90
commit 3b1a4f5f94
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30
src/basics.md
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@ -27,6 +27,7 @@
| [Check number of logical cpu cores][ex-check-cpu-cores] | [![num_cpus-badge]][num_cpus] | [![cat-hardware-support-badge]][cat-hardware-support] |
| [Obtain backtrace of complex error scenarios][ex-error-chain-backtrace] | [![error-chain-badge]][error-chain] | [![cat-rust-patterns-badge]][cat-rust-patterns] |
| [Measure elapsed time][ex-measure-elapsed-time] | [![std-badge]][std] | [![cat-time-badge]][cat-time] |
| [Convert a local time to an another UTC timezone and vice versa][ex-convert-datetime-timezone] | [![chrono-badge]][chrono] | [![cat-date-and-time-badge]][cat-date-and-time] |
| [Display formatted date and time][ex-format-datetime] | [![chrono-badge]][chrono] | [![cat-date-and-time-badge]][cat-date-and-time] |
| [Parse string into DateTime struct][ex-parse-datetime] | [![chrono-badge]][chrono] | [![cat-date-and-time-badge]][cat-date-and-time] |
| [Perform checked date and time calculations][ex-datetime-arithmetic] | [![chrono-badge]][chrono] | [![cat-date-and-time-badge]][cat-date-and-time] |
@ -1266,6 +1267,32 @@ fn main() {
println!("Time elapsed in expensive_function() is: {:?}", duration);
}
```
[ex-convert-datetime-timezone]: #ex-convert-datetime-timezone
<a name="ex-convert-datetime-timezone"></a>
## Convert a local time to an another UTC timezone and vice versa
[![chrono-badge]][chrono] [![cat-date-and-time-badge]][cat-date-and-time]
Gets the local time and displays it using [`offset::Local::now`] and then converts it to the UTC standard using the [`DateTime::from_utc`] struct method. A time is then converted using the [`offset::FixedOffset`] struct and the UTC time is then converted to UTC+8 and UTC-2.
```rust
extern crate chrono;
use chrono::{DateTime, FixedOffset, Local, Utc};
fn main() {
let local_time = Local::now();
let utc_time = DateTime::<Utc>::from_utc(local_time.naive_utc(), Utc);
let china_timezone = FixedOffset::east(8 * 3600);
let rio_timezone = FixedOffset::west(2 * 3600);
println!("Local time now is {}", local_time);
println!("UTC time now is {}", utc_time);
println!(
"Time in Hong Kong now is {}",
utc_time.with_timezone(&china_timezone)
);
println!("Time in Rio de Janeiro now is {}", utc_time.with_timezone(&rio_timezone));
}
```
[ex-format-datetime]: #ex-format-datetime
<a name="ex-format-datetime"></a>
@ -1451,6 +1478,7 @@ fn main() {
[`DateTime::to_rfc2822`]: https://docs.rs/chrono/*/chrono/struct.DateTime.html#method.to_rfc2822
[`DateTime::to_rfc3339`]: https://docs.rs/chrono/*/chrono/struct.DateTime.html#method.to_rfc3339
[`DateTime::format`]: https://docs.rs/chrono/*/chrono/struct.DateTime.html#method.format
[`DateTime::from_utc`]:https://docs.rs/chrono/*/chrono/struct.DateTime.html#method.from_utc
[`DateTime::checked_add_signed`]: https://docs.rs/chrono/*/chrono/struct.Date.html#method.checked_add_signed
[`DateTime::checked_sub_signed`]: https://docs.rs/chrono/*/chrono/struct.Date.html#method.checked_sub_signed
[`DateTime`]: https://docs.rs/chrono/*/chrono/struct.DateTime.html
@ -1474,6 +1502,8 @@ fn main() {
[`Normal`]: https://doc.rust-lang.org/rand/rand/distributions/normal/struct.Normal.html
[`num_cpus::get`]: https://docs.rs/num_cpus/*/num_cpus/fn.get.html
[`Output`]: https://doc.rust-lang.org/std/process/struct.Output.html
[`offset::FixedOffset`]: https://docs.rs/chrono/*/chrono/offset/struct.FixedOffset.html
[`offset::Local::now`]: https://docs.rs/chrono/*/chrono/offset/struct.Local.html#method.now
[`pbkdf2::derive`]: https://docs.rs/ring/*/ring/pbkdf2/fn.derive.html
[`pbkdf2::verify`]: https://docs.rs/ring/*/ring/pbkdf2/fn.verify.html
[`process::Stdio`]: https://doc.rust-lang.org/std/process/struct.Stdio.html

2
src/intro.md
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@ -45,6 +45,7 @@ community. It needs and welcomes help. For details see
| [Check number of logical cpu cores][ex-check-cpu-cores] | [![num_cpus-badge]][num_cpus] | [![cat-hardware-support-badge]][cat-hardware-support] |
| [Obtain backtrace of complex error scenarios][ex-error-chain-backtrace] | [![error-chain-badge]][error-chain] | [![cat-rust-patterns-badge]][cat-rust-patterns] |
| [Measure elapsed time][ex-measure-elapsed-time] | [![std-badge]][std] | [![cat-time-badge]][cat-time] |
| [Convert a local time to an another UTC timezone and vice versa][ex-convert-datetime-timezone] | [![chrono-badge]][chrono] | [![cat-date-and-time-badge]][cat-date-and-time] |
| [Display formatted date and time][ex-format-datetime] | [![chrono-badge]][chrono] | [![cat-date-and-time-badge]][cat-date-and-time] |
| [Parse string into DateTime struct][ex-parse-datetime] | [![chrono-badge]][chrono] | [![cat-date-and-time-badge]][cat-date-and-time] |
| [Perform checked date and time calculations][ex-datetime-arithmetic] | [![chrono-badge]][chrono] | [![cat-date-and-time-badge]][cat-date-and-time] |
@ -161,6 +162,7 @@ community. It needs and welcomes help. For details see
[ex-check-broken-links]: net.html#ex-check-broken-links
[ex-check-cpu-cores]: basics.html#ex-check-cpu-cores
[ex-clap-basic]: app.html#ex-clap-basic
[ex-convert-datetime-timezone]: basics.html#ex-convert-datetime-timezone
[ex-crossbeam-spawn]: concurrency.html#ex-crossbeam-spawn
[ex-csv-delimiter]: encoding.html#ex-csv-delimiter
[ex-csv-filter]: encoding.html#ex-csv-filter