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

branch: master
README.md

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 "0.6.0"]

With Maven:

<dependency>
  <groupId>clj-time</groupId>
  <artifactId>clj-time</artifactId>
  <version>0.6.0</version>
</dependency>

Bugs and Enhancements

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

Note: version 0.6.0 introduces a number of API changes to improve consistency. The API now uses second, seconds and millis where it previously had sec, secs and msecs. The older API is still present but marked as deprecated (and calling deprecated functions will print a message to the console as well returning the result). The older API will be removed in version 0.7.0 so be prepared to update your code.

Usage

clj-time.core

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

=> (use 'clj-time.core)

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

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

Less-significant fields can be omitted:

=> (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:

=> (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:

=> (from-time-zone (date-time 1986 10 22) (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:

=> (to-time-zone (date-time 1986 10 22) (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).

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

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

=> (after? (date-time 1986 10) (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:

=> (plus (date-time 1986 10 14) (months 1) (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?

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

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

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

clj-time.format

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

=> (use 'clj-time.format)

Printing 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 (formatters :basic-date-time))
(def custom-formatter (formatter "yyyyMMdd"))

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

=> (show-formatters)

Remember that mm is minutes, MM is months, ss is seconds and SS is milliseconds.

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

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

=> (unparse custom-formatter (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 (formatter (default-time-zone) "YYYY-MM-dd" "YYYY/MM/dd"))

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

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

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

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

clj-time.coerce

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

=> (use 'clj-time.coerce)

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

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

=> (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:

=> (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.

Get the current local time with

=> (local-now)

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

=> (to-local-date-time obj)

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

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

=> (format-local-time (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:

(use 'clj-time.periodic)
(use 'clj.time.core)

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

Development

Running the tests:

$ lein test-all

(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

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