(PHP 4 >= 4.1.0, PHP 5, PHP 7)
cal_days_in_month — 返回某个历法中某年中某月的天数
$calendar
, int $month
, int $year
)
该函数返回特定历法中的某年中的某月的天数。
calendar用来计算的某个历法
month选定历法中的某月
year选定历法中的某年
指定历法中选定的某月的天数。
Example #1 cal_days_in_month() example
<?php
$num = cal_days_in_month(CAL_GREGORIAN, 8, 2003); // 31
echo "There was $num days in August 2003";
?>
Simplest one for string date like bellow;
$date = '2017-01-28';
echo date(' t ', strtotime($date) );
Output :
31
strtotime() will convert string date to timestamp and date function will return specified format in this case ' t ' means total number of days in month.
To get the number of days in a given month, you just need to pass a timestamp that occurs during that month to the date function.
I've found this is beneficial when I cannot guarantee a particular set of functionality has been compiled into a given PHP installation.
<?php
$month = "2"
$year = "2014"
date("t",mktime(0,0,0,$month,1,$year));
//equivalent to
date("t",mktime(0,0,0,2,1,2014));
//returns 28
?>
If you have a DateTime variable you want to find the number of days in the month for, you can simply use $dt->format and the format specifiers 'm' and 'Y' to get the month digit, and year to use with cal_days_in_month eg.
function DaysInMonth($dt) {
$m = $dt->format('m');
$y = $dt->format('Y');
$numDays = cal_days_in_month (CAL_GREGORIAN, $m,$y);
return $numDays;
}
count specific days in a month like how many satureday in a monday or how many mondays in a month
<?php
function my_cal_days_in_month($year,$month,$calday="1"){ //0 Sunday, 1 Monday, 2 Tue , 3 Wed , 4. Thu , 5. Fri , 6. Sat
// calculate total number of occurance in this month
$num = cal_days_in_month(CAL_GREGORIAN, $month, $year); // days in month
$dayofweek = date( "w", mktime(0, 0, 0, $month, 1, $year));
$adddays=0;
if($calday > $dayofweek )
$adddays=1 + $calday - $dayofweek;
else if($calday < $dayofweek )
$adddays=1 + 7 + ($calday - $dayofweek );
$remainingdays=$num-$adddays;
$leavesnum=1+intval($remainingdays / 7);
return $leavesnum;
}
$year=2013;
$month=7;
$day=6;
echo my_cal_days_in_month($year,$month,$day);
You can also use the date() function to get the number of days in a month. You can also pass the 2nd param strtotime() and specify a specific date:
date('t');
Forgot to compile the calendar plugin in... Wrote a workaround while I waited for it to compile. It only supports the Gregorian calendar.
<?php
if (!function_exists('cal_days_in_month'))
{
function cal_days_in_month($calendar, $month, $year)
{
return date('t', mktime(0, 0, 0, $month, 1, $year));
}
}
if (!defined('CAL_GREGORIAN'))
define('CAL_GREGORIAN', 1);
?>
Function for calculation number of days until birthday:
<?php
function daysLeftForBirthday($devabirthdate)
{
/* input birthday date format -> Y-m-d */
list($y, $m, $d) = explode('-',$devabirthdate);
$nowdate = mktime(0, 0, 0, date("m"), date("d"), date("Y"));
$nextbirthday = mktime(0,0,0,$m, $d, date("Y"));
if ($nextbirthday<$nowdate)
$nextbirthday=$nextbirthday+(60*60*24*365);
$daycount=intval(($nextbirthday-$nowdate)/(60*60*24));
return $daycount;
}
?>
Remember if you just want the days in the current month, use the date function:
$days = date("t");
<?php
# PHP Calendar (version 2.3), written by Keith Devens
function generate_calendar($year, $month, $days = array(), $day_name_length = 3, $month_href = NULL, $first_day = 0, $pn = array()){
$first_of_month = gmmktime(0,0,0,$month,1,$year);
#remember that mktime will automatically correct if invalid dates are entered
# for instance, mktime(0,0,0,12,32,1997) will be the date for Jan 1, 1998
# this provides a built in "rounding" feature to generate_calendar()
$day_names = array(); #generate all the day names according to the current locale
for($n=0,$t=(3+$first_day)*86400; $n<7; $n++,$t+=86400) #January 4, 1970 was a Sunday
$day_names[$n] = ucfirst(gmstrftime('%A',$t)); #%A means full textual day name
list($month, $year, $month_name, $weekday) = explode(',',gmstrftime('%m,%Y,%B,%w',$first_of_month));
$weekday = ($weekday + 7 - $first_day) % 7; #adjust for $first_day
$title = htmlentities(ucfirst($month_name)).' '.$year; #note that some locales don't capitalize month and day names
#Begin calendar. Uses a real <caption>. See http://diveintomark.org/archives/2002/07/03
@list($p, $pl) = each($pn); @list($n, $nl) = each($pn); #previous and next links, if applicable
if($p) $p = '<span class="calendar-prev">'.($pl ? '<a href="'.htmlspecialchars($pl).'">'.$p.'</a>' : $p).'</span> ';
if($n) $n = ' <span class="calendar-next">'.($nl ? '<a href="'.htmlspecialchars($nl).'">'.$n.'</a>' : $n).'</span>';
$calendar = '<table class="calendar">'."\n".
'<caption class="calendar-month">'.$p.($month_href ? '<a href="'.htmlspecialchars($month_href).'">'.$title.'</a>' : $title).$n."</caption>\n<tr>";
if($day_name_length){ #if the day names should be shown ($day_name_length > 0)
#if day_name_length is >3, the full name of the day will be printed
foreach($day_names as $d)
$calendar .= '<th abbr="'.htmlentities($d).'">'.htmlentities($day_name_length < 4 ? substr($d,0,$day_name_length) : $d).'</th>';
$calendar .= "</tr>\n<tr>";
}
if($weekday > 0) $calendar .= '<td colspan="'.$weekday.'"> </td>'; #initial 'empty' days
for($day=1,$days_in_month=gmdate('t',$first_of_month); $day<=$days_in_month; $day++,$weekday++){
if($weekday == 7){
$weekday = 0; #start a new week
$calendar .= "</tr>\n<tr>";
}
if(isset($days[$day]) and is_array($days[$day])){
@list($link, $classes, $content) = $days[$day];
if(is_null($content)) $content = $day;
$calendar .= '<td'.($classes ? ' class="'.htmlspecialchars($classes).'">' : '>').
($link ? '<a href="'.htmlspecialchars($link).'">'.$content.'</a>' : $content).'</td>';
}
else $calendar .= "<td>$day</td>";
}
if($weekday != 7) $calendar .= '<td colspan="'.(7-$weekday).'"> </td>'; #remaining "empty" days
return $calendar."</tr>\n</table>\n";
}
echo generate_calendar(2010, 12, 16,3,NULL,0,15, $first_of_month, $day_names, $day_names[$n]);
#echo generate_calendar($year, $month, $days,$day_name_length,$month_href,$first_day,$pn);
?>
This will work great in future dates but will give the wrong answer for dates before 1550 (approx) when leap year was introduced and the calendar lost a year or two.
Sorry now to be more specific it has been a while sine I had to account for those later dates and had to take that into account but just a heads up for others to watch out.
Here's a one-line function I just wrote to find the numbers of days in a month that doesn't depend on any other functions.
The reason I made this is because I just found out I forgot to compile PHP with support for calendars, and a class I'm writing for my website's open source section was broken. So rather than recompiling PHP (which I will get around to tomorrow I guess), I just wrote this function which should work just as well, and will always work without the requirement of PHP's calendar extension or any other PHP functions for that matter.
I learned the days of the month using the old knuckle & inbetween knuckle method, so that should explain the mod 7 part. :)
<?php
/*
* days_in_month($month, $year)
* Returns the number of days in a given month and year, taking into account leap years.
*
* $month: numeric month (integers 1-12)
* $year: numeric year (any integer)
*
* Prec: $month is an integer between 1 and 12, inclusive, and $year is an integer.
* Post: none
*/
// corrected by ben at sparkyb dot net
function days_in_month($month, $year)
{
// calculate number of days in a month
return $month == 2 ? ($year % 4 ? 28 : ($year % 100 ? 29 : ($year % 400 ? 28 : 29))) : (($month - 1) % 7 % 2 ? 30 : 31);
}
?>
Enjoy,
David Bindel