Checking For Leap Year Using PHP
One part of programming that seems pretty static is dealing with dates. The calendar is a set system of rules that doesn't look to change. The only part of the calendar that can be variable is a leap year, which changes every four years (obviously).
Using pure PHP ternary logic, much like the PHP Function - Calculating Days In A Month, I posted a few weeks back, you can check to see if a year is a leap year.
The Code
function is_leap_year($year) {
return ((($year % 4) == 0) && ((($year % 100) != 0) || (($year % 400) == 0)));
}
![7 Essential JavaScript Functions]()
I remember the early days of JavaScript where you needed a simple function for just about everything because the browser vendors implemented features differently, and not just edge features, basic features, like addEventListener and attachEvent. Times have changed but there are still a few functions each developer should...
![Regular Expressions for the Rest of Us]()
Sooner or later you'll run across a regular expression. With their cryptic syntax, confusing documentation and massive learning curve, most developers settle for copying and pasting them from StackOverflow and hoping they work. But what if you could decode regular expressions and harness their power? In...
![GitHub-Style Sliding Links]()
GitHub seems to change a lot but not really change at all, if that makes any sense; the updates come often but are always fairly small. I spotted one of the most recent updates on the pull request page. Links to long branch...
![Image Data URIs with PHP]()
If you troll page markup like me, you've no doubt seen the use of data URI's within image src attributes. Instead of providing a traditional address to the image, the image file data is base64-encoded and stuffed within the src attribute. Doing so saves...
Placing a function call as an argument default will result in a fatal error. Also, give this version a shot:
function is_leap_year( $year = NULL ) { if_numeric( $year ) || $year = date( 'Y' ); return checkdate( 2, 29, ( int ) $year ); }Whoops, small typo… if_numeric( $year ) should be is_numeric( $year )… :x
Better yet, use
date('L')which returns1if it’s a leap year,0if it isn’t.I do agree with tamlyn, why you dont use date function??
It can makes a load fasting right?
date(‘L’) is way better because leap year is not every 4 years.
Date("L")only tell you in a given year, default is the year today.If you need to know whether previous or next year is a leap, you must reset the date.
It could affect the system.
Indra, you can always pass the timestamp as second parameter to date function:
echo date('L', mktime(1, 1, 1, 1, 1, 2005));I think this is a better example relating to the function. Also provided example for anyone looking for true/false as I was in this instance.
/* for true or false */ function is_leap_year($year) { return ( date ('L', mktime(1,1,1,1,1, $year) ) === 1 ) ? true : false; } /*for 0 or 1 Whether it's a leap year: 1 if it is a leap year, 0 otherwise. */ function is_leap_year($year) { return date ('L', mktime(1,1,1,1,1, $year) ); }<?php $day = ""; for($i=0; $i<4; $i++) { $day = date("d", mktime(0, 0, 0, 2, 29, date("Y")+$i)); if($day == 29) { $year = date("Y")+$i; break; } } echo "The next leap year is 29th February $year"; ?>code of Habibur Rahaman will not work for example for the year 1897, because 1900 is not leap year.