cal_days_in_month()

(PHP 4 >= 4.1.0, PHP 5, PHP 7)

返回某个历法中某年中某月的天数

说明

cal_days_in_month(int $calendar,int $month,int $year): int

该函数返回特定历法中的某年中的某月的天数。

参数

$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

返回值

指定历法中选定的某月的天数。

范例

cal_days_in_month() example

<?php
$num = cal_days_in_month(CAL_GREGORIAN, 8, 2003); // 31
echo "There was $num days in August 2003";
?>

Remember if you just want the days in the current month, use the date function:
$days = date("t");

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

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.

<?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)).'&nbsp;'.$year; #note that some locales don't capitalize month and day names
  #Begin calendar. Uses a real <caption>. See http://diveintomark.org/archives/2002/07/03
  @list($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>' : $p).'</span>&nbsp;';
  if($n) $n = '&nbsp;<span class="calendar-next">'.($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.'">&nbsp;</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).'">&nbsp;</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);
?>