Date function in PHP

What is Date function in PHP ?

The date() function in PHP  formats a local date and time, and returns the formatted date string.

Syntax :date(format,timestamp);

for example


<?php
echo date("Y/m/d") . "<br>";
echo  date("Y.m.d") . "<br>";
echo date("Y-m-d") . "<br>";
echo  date("l");
?>

output will be:

2016/07/28
2016.07.28
2016-07-28
Thursday

Parameter Description
format Required. Specifies the format of the outputted date string. The following characters can be used:

  • d – The day of the month (from 01 to 31)
  • D – A textual representation of a day (three letters)
  • j – The day of the month without leading zeros (1 to 31)
  • l (lowercase ‘L’) – A full textual representation of a day
  • N – The ISO-8601 numeric representation of a day (1 for Monday, 7 for Sunday)
  • S – The English ordinal suffix for the day of the month (2 characters st, nd, rd or th. Works well with j)
  • w – A numeric representation of the day (0 for Sunday, 6 for Saturday)
  • z – The day of the year (from 0 through 365)
  • W – The ISO-8601 week number of year (weeks starting on Monday)
  • F – A full textual representation of a month (January through December)
  • m – A numeric representation of a month (from 01 to 12)
  • M – A short textual representation of a month (three letters)
  • n – A numeric representation of a month, without leading zeros (1 to 12)
  • t – The number of days in the given month
  • L – Whether it’s a leap year (1 if it is a leap year, 0 otherwise)
  • o – The ISO-8601 year number
  • Y – A four digit representation of a year
  • y – A two digit representation of a year
  • a – Lowercase am or pm
  • A – Uppercase AM or PM
  • B – Swatch Internet time (000 to 999)
  • g – 12-hour format of an hour (1 to 12)
  • G – 24-hour format of an hour (0 to 23)
  • h – 12-hour format of an hour (01 to 12)
  • H – 24-hour format of an hour (00 to 23)
  • i – Minutes with leading zeros (00 to 59)
  • s – Seconds, with leading zeros (00 to 59)
  • u – Microseconds (added in PHP 5.2.2)
  • e – The timezone identifier (Examples: UTC, GMT, Atlantic/Azores)
  • I (capital i) – Whether the date is in daylights savings time (1 if Daylight Savings Time, 0 otherwise)
  • O – Difference to Greenwich time (GMT) in hours (Example: +0100)
  • P – Difference to Greenwich time (GMT) in hours:minutes (added in PHP 5.1.3)
  • T – Timezone abbreviations (Examples: EST, MDT)
  • Z – Timezone offset in seconds. The offset for timezones west of UTC is negative (-43200 to 50400)
  • c – The ISO-8601 date (e.g. 2013-05-05T16:34:42+00:00)
  • r – The RFC 2822 formatted date (e.g. Fri, 12 Apr 2013 12:01:05 +0200)
  • U – The seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)

and the following predefined constants can also be used (available since PHP 5.1.0):

  • DATE_ATOM – Atom (example: 2013-04-12T15:52:01+00:00)
  • DATE_COOKIE – HTTP Cookies (example: Friday, 12-Apr-13 15:52:01 UTC)
  • DATE_ISO8601 – ISO-8601 (example: 2013-04-12T15:52:01+0000)
  • DATE_RFC822 – RFC 822 (example: Fri, 12 Apr 13 15:52:01 +0000)
  • DATE_RFC850 – RFC 850 (example: Friday, 12-Apr-13 15:52:01 UTC)
  • DATE_RFC1036 – RFC 1036 (example: Fri, 12 Apr 13 15:52:01 +0000)
  • DATE_RFC1123 – RFC 1123 (example: Fri, 12 Apr 2013 15:52:01 +0000)
  • DATE_RFC2822 – RFC 2822 (Fri, 12 Apr 2013 15:52:01 +0000)
  • DATE_RFC3339 – Same as DATE_ATOM (since PHP 5.1.3)
  • DATE_RSS – RSS (Fri, 12 Aug 2013 15:52:01 +0000)
  • DATE_W3C – World Wide Web Consortium (example: 2013-04-12T15:52:01+00:00)
timestamp Optional. Specifies an integer Unix timestamp. Default is the current local time (time())

time() give the number of  second since 1 st jan 1970 00:00:01

base date in PHP is Consider  number of seconds since 1 st jan 1970 00:00:01

To know how many seconds, minutes, hours, days, years are since is give as


$s=time();
echo "<br/>Number of seconds is $s";
$m=$s/60;
echo "<br/>Number of minutes is $m";
$h=$m/60;
echo "<br/>Number of hours is $h";
$d=$h/24;
echo "<br/>Number of days is $d";
$y=$d/365;
echo "<br/>Number of years is $y";

How to Validate Date  in PHP ?

to understand  take an example $d=29; $m=2; $y=2016; if(checkdate($m,$d,$y)) //validates a date echo "<br/>valid date"; else echo "<br/>Invalid date";