# CodeIgniter User Guide Version 2.1.1

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# Date Helper

The Date Helper file contains functions that help you work with dates.

## Loading this Helper

This helper is loaded using the following code:

`$this->load->helper('date');`

The following functions are available:

## now()

Returns the current time as a Unix timestamp, referenced either to your server's local time or GMT, based on the "time reference" setting in your config file. If you do not intend to set your master time reference to GMT (which you'll typically do if you run a site that lets each user set their own timezone settings) there is no benefit to using this function over PHP's time() function.

## mdate()

This function is identical to PHPs date() function, except that it lets you use MySQL style date codes, where each code letter is preceded with a percent sign: %Y %m %d etc.

The benefit of doing dates this way is that you don't have to worry about escaping any characters that are not date codes, as you would normally have to do with the date() function. Example:

`$datestring = "Year: %Y Month: %m Day: %d - %h:%i %a";
$time = time();
echo mdate($datestring, $time);`

If a timestamp is not included in the second parameter the current time will be used.

## standard_date()

Lets you generate a date string in one of several standardized formats. Example:

`$format = 'DATE_RFC822';
$time = time();
echo standard_date($format, $time);`

The first parameter must contain the format, the second parameter must contain the date as a Unix timestamp.

Supported formats:

Constant | Description | Example
--- | --- | ---
DATE_ATOM | Atom | 2005-08-15T16:13:03+0000
DATE_COOKIE | HTTP Cookies | Sun, 14 Aug 2005 16:13:03 UTC
DATE_ISO8601 | ISO-8601 | 2005-08-14T16:13:03+00:00
DATE_RFC822 | RFC 822 | Sun, 14 Aug 05 16:13:03 UTC
DATE_RFC850 | RFC 850 | Sunday, 14-Aug-05 16:13:03 UTC
DATE_RFC1036 | RFC 1036 | Sunday, 14-Aug-05 16:13:03 UTC
DATE_RFC1123 | RFC 1123 | Sun, 14 Aug 2005 16:13:03 UTC
DATE_RFC2822 | RFC 2822 | Sun, 14 Aug 2005 16:13:03 +0000
DATE_RSS | RSS | Sun, 14 Aug 2005 16:13:03 UTC
DATE_W3C | World Wide Web Consortium | 2005-08-14T16:13:03+0000

## local_to_gmt()

Takes a Unix timestamp as input and returns it as GMT. Example:

`$now = time();
$gmt = local_to_gmt($now);`

## gmt_to_local()

Takes a Unix timestamp (referenced to GMT) as input, and converts it to a localized timestamp based on the timezone and Daylight Saving time submitted. Example:

`$timestamp = '1140153693';
$timezone = 'UM8';
$daylight_saving = TRUE;
echo gmt_to_local($timestamp, $timezone, $daylight_saving);`

Note: For a list of timezones see the reference at the bottom of this page.

## mysql_to_unix()

Takes a MySQL Timestamp as input and returns it as Unix. Example:

`$mysql = '20061124092345';
$unix = mysql_to_unix($mysql);`

## unix_to_human()

Takes a Unix timestamp as input and returns it in a human readable format with this prototype:

`YYYY-MM-DD HH:MM:SS AM/PM`

This can be useful if you need to display a date in a form field for submission.

The time can be formatted with or without seconds, and it can be set to European or US format. If only the timestamp is submitted it will return the time without seconds formatted for the U.S. Examples:

`$now = time();
echo unix_to_human($now); // U.S. time, no seconds
echo unix_to_human($now, TRUE, 'us'); // U.S. time with seconds
echo unix_to_human($now, TRUE, 'eu'); // Euro time with seconds`

## human_to_unix()

The opposite of the above function. Takes a "human" time as input and returns it as Unix. This function is useful if you accept "human" formatted dates submitted via a form. Returns FALSE (boolean) if the date string passed to it is not formatted as indicated above. Example:

`$now = time();
$human = unix_to_human($now);
$unix = human_to_unix($human);`

## timespan()

Formats a unix timestamp so that is appears similar to this:

`1 Year, 10 Months, 2 Weeks, 5 Days, 10 Hours, 16 Minutes`

The first parameter must contain a Unix timestamp. The second parameter must contain a timestamp that is greater that the first timestamp. If the second parameter empty, the current time will be used. The most common purpose for this function is to show how much time has elapsed from some point in time in the past to now. Example:

`$post_date = '1079621429';
$now = time();
echo timespan($post_date, $now);`

Note: The text generated by this function is found in the following language file: language/<your_lang>/date_lang.php

## days_in_month()

Returns the number of days in a given month/year. Takes leap years into account. Example:

`echo days_in_month(06, 2005);`

If the second parameter is empty, the current year will be used.

## timezones()

Takes a timezone reference (for a list of valid timezones, see the "Timezone Reference" below) and returns the number of hours offset from UTC.

`echo timezones('UM5');`

This function is useful when used with timezone_menu().

## timezone_menu()

Generates a pull-down menu of timezones, like this one:

This menu is useful if you run a membership site in which your users are allowed to set their local timezone value.

The first parameter lets you set the "selected" state of the menu. For example, to set Pacific time as the default you will do this:

`echo timezone_menu('UM8');`

Please see the timezone reference below to see the values of this menu.

The second parameter lets you set a CSS class name for the menu.

Note: The text contained in the menu is found in the following language file: language/<your_lang>/date_lang.php

## Timezone Reference

The following table indicates each timezone and its location.

Time Zone | Location
--- | ---
UM12 | (UTC - 12:00) Enitwetok, Kwajalien
UM11 | (UTC - 11:00) Nome, Midway Island, Samoa
UM10 | (UTC - 10:00) Hawaii
UM9 | (UTC - 9:00) Alaska
UM8 | (UTC - 8:00) Pacific Time
UM7 | (UTC - 7:00) Mountain Time
UM6 | (UTC - 6:00) Central Time, Mexico City
UM5 | (UTC - 5:00) Eastern Time, Bogota, Lima, Quito
UM4 | (UTC - 4:00) Atlantic Time, Caracas, La Paz
UM25 | (UTC - 3:30) Newfoundland
UM3 | (UTC - 3:00) Brazil, Buenos Aires, Georgetown, Falkland Is.
UM2 | (UTC - 2:00) Mid-Atlantic, Ascention Is., St Helena
UM1 | (UTC - 1:00) Azores, Cape Verde Islands
UTC | (UTC) Casablanca, Dublin, Edinburgh, London, Lisbon, Monrovia
UP1 | (UTC + 1:00) Berlin, Brussels, Copenhagen, Madrid, Paris, Rome
UP2 | (UTC + 2:00) Kaliningrad, South Africa, Warsaw
UP3 | (UTC + 3:00) Baghdad, Riyadh, Moscow, Nairobi
UP25 | (UTC + 3:30) Tehran
UP4 | (UTC + 4:00) Adu Dhabi, Baku, Muscat, Tbilisi
UP35 | (UTC + 4:30) Kabul
UP5 | (UTC + 5:00) Islamabad, Karachi, Tashkent
UP45 | (UTC + 5:30) Bombay, Calcutta, Madras, New Delhi
UP6 | (UTC + 6:00) Almaty, Colomba, Dhaka
UP7 | (UTC + 7:00) Bangkok, Hanoi, Jakarta
UP8 | (UTC + 8:00) Beijing, Hong Kong, Perth, Singapore, Taipei
UP9 | (UTC + 9:00) Osaka, Sapporo, Seoul, Tokyo, Yakutsk
UP85 | (UTC + 9:30) Adelaide, Darwin
UP10 | (UTC + 10:00) Melbourne, Papua New Guinea, Sydney, Vladivostok
UP11 | (UTC + 11:00) Magadan, New Caledonia, Solomon Islands
UP12 | (UTC + 12:00) Auckland, Wellington, Fiji, Marshall Island