clj-time

A date and time library for Clojure, wrapping the Joda Time library.

Artifacts

clj-time artifacts are released to Clojars.

If you are using Maven, add the following repository definition to your pom.xml:

<repository>
  <id>clojars.org</id>
  <url>http://clojars.org/repo</url>
</repository>

The Most Recent Release

With Leiningen:

[clj-time "0.9.0"]

With Maven:

<dependency>
  <groupId>clj-time</groupId>
  <artifactId>clj-time</artifactId>
  <version>0.9.0</version>
</dependency>

Bugs and Enhancements

Please open issues against the official clj-time repo on Github.

Mailing List

Please ask questions on the clj-time mailing list.

Usage

clj-time.core

The main namespace for date-time operations in the clj-time library is clj-time.core.

=> (require '[clj-time.core :as t])

Create a DateTime instance with date-time, specifying the year, month, day, hour, minute, second, and millisecond:

(t/date-time 1986 10 14 4 3 27 456)
=> #<DateTime 1986-10-14T04:03:27.456Z>

Less-significant fields can be omitted:

(t/date-time 1986 10 14)
=> #<DateTime 1986-10-14T00:00:00.000Z>

Get the current time with now and the start of the Unix epoch with epoch.

Once you have a date-time, use accessors like hour and second to access the corresponding fields:

(t/hour (date-time 1986 10 14 22))
=> 22

The date-time constructor always returns times in the UTC time zone. If you want a time with the specified fields in a different time zone, use from-time-zone:

(t/from-time-zone (t/date-time 1986 10 22) (t/time-zone-for-offset -2))
=> #<DateTime 1986-10-22T00:00:00.000-02:00>

If on the other hand you want a given absolute instant in time in a different time zone, use to-time-zone:

(t/to-time-zone (t/date-time 1986 10 22) (t/time-zone-for-offset -2))
=> #<DateTime 1986-10-21T22:00:00.000-02:00>

In addition to time-zone-for-offset, you can use the time-zone-for-id and default-time-zone functions and the utc Var to construct or get DateTimeZone instances.

If you only want a date with no time component, consider using the local-date and today functions. These return LocalDate instances that do not have time components (and thus don't suffer from timezone-related shifting).

(t/local-date 2013 3 20)
=> #<LocalDate 2013-03-20>

The functions after? and before? determine the relative position of two DateTime instances:

(t/after? (t/date-time 1986 10) (t/date-time 1986 9))
=> true

Often you will want to find a date some amount of time from a given date. For example, to find the time 1 month and 3 weeks from a given date-time:

(t/plus (t/date-time 1986 10 14) (t/months 1) (t/weeks 3))
=> #<DateTime 1986-12-05T00:00:00.000Z>

An Interval is used to represent the span of time between two DateTime instances. Construct one using interval, then query them using within?, overlaps?, and abuts?

(t/within? (t/interval (t/date-time 1986) (t/date-time 1990))
              (t/date-time 1987))
=> true

The in-seconds and in-minutes functions can be used to describe intervals in the corresponding temporal units:

(t/in-minutes (t/interval (t/date-time 1986 10 2) (t/date-time 1986 10 14)))
=> 17280

today-at returns a moment in time at the given hour, minute and second on the current date:

(t/today-at 12 00)
=> #<DateTime 2013-03-29T12:00:00.000Z>
(t/today-at 12 00 05)
=> #<DateTime 2013-03-29T12:00:05.000Z>

clj-time.format

If you need to parse or print date-times, use clj-time.format:

(require '[clj-time.format :as f])

Parsing and printing are controlled by formatters. You can either use one of the built in ISO8601 formatters or define your own, e.g.:

(def built-in-formatter (f/formatters :basic-date-time))
(def custom-formatter (f/formatter "yyyyMMdd"))

To see a list of available built-in formatters and an example of a date-time printed in their format:

(f/show-formatters)

Remember that mm is minutes, MM is months, ss is seconds and SS is milliseconds. You can find a complete list of patterns on the Joda Time website.

Once you have a formatter, parsing and printing are straightforward:

(f/parse custom-formatter "20100311")
=> #<DateTime 2010-03-11T00:00:00.000Z>

(f/unparse custom-formatter (t/date-time 2010 10 3))
=> "20101003"

To parse dates in multiple formats and format dates in just one format, you can do this:

(def multi-parser (f/formatter (t/default-time-zone) "YYYY-MM-dd" "YYYY/MM/dd"))

(f/unparse multi-parser (f/parse multi-parser "2012-02-01"))
=> "2012-02-01"

(f/unparse multi-parser (f/parse multi-parser "2012/02/01"))
=> "2012-02-01"

clj-time.coerce

The namespace clj-time.coerce contains utility functions for coercing Joda DateTime instances to and from various other types:

(require '[clj-time.coerce :as c])

For example, to convert a Joda DateTime to and from a Java long:

(c/to-long (t/date-time 1998 4 25))
=> 893462400000

(c/from-long 893462400000)
=> #<DateTime 1998-04-25T00:00:00.000Z>

And by the magic of protocols you can pass in an isoformat string and get the unix epoch milliseconds:

(c/to-long "2013-08-01")
=> 1375315200000

There are also conversions to and from java.util.Date (to-date and from-date), java.sql.Date (to-sql-date and from-sql-date), java.sql.Timestamp (to-sql-time and from-sql-time) and several other types.

clj-time.local

The namespace clj-time.local contains functions for working with local time without having to shift to/from utc, the preferred time zone of clj-time.core.

(require '[clj-time.local :as l])

Get the current local time with

(l/local-now)

Get a local date-time instance retaining the time fields with

(l/to-local-date-time obj)

The following all return 1986-10-14 04:03:27.246 with the local time zone.

(l/to-local-date-time (clj-time.core/date-time 1986 10 14 4 3 27 246))
(l/to-local-date-time "1986-10-14T04:03:27.246")
(l/to-local-date-time "1986-10-14T04:03:27.246Z")

The dynamic var *local-formatters* contains a map of local formatters for parsing and printing. It is initialized with all the formatters in clj-time.format localized.

to-local-date-time for strings uses *local-formatters* to parse.

Format an obj using a formatter in *local-formatters* corresponding to the format-key passed in with

(l/format-local-time (l/local-now) :basic-date-time)

clj-time.periodic

clj-time.periodic/periodic-seq returns an infinite sequence of instants separated by a time period starting with the given point in time:

(require '[clj-time.periodic :as p])
(require '[clj-time.core :as t])

;; returns 10 instants starting with current time separated
;; by 12 hours
(take 10 (p/periodic-seq (t/now) (t/hours 12)))

clj-time.predicates

clj-time.predicates comes with a set of handy predicates to check for common conditions. For instance:

(require '[clj-time.core :as t])
(require '[clj-time.predicates :as pr])

(pr/monday? (t/date-time 1999 9 9))
=> false

(pr/january? (t/date-time 2011 1 1))
=> true

(pr/weekend? (t/date-time 2014 1 26))
=> true

(pr/weekday? (t/date-time 2014 1 26))
=> false

(pr/last-day-of-month? (t/date-time 2014 1 26))
=> false

(pr/first-day-of-month? (t/date-time 2014 1 26))
=> false

Development

Running the tests:

$ rm -f test/readme.clj && lein test-all && lein test-readme

(assumes Leiningen 2.x)

Documentation

The complete API documentation is also available (codox generated).

License

Released under the MIT License: https://github.com/clj-time/clj-time/blob/master/MIT-LICENSE.txt