PHP/String/strtotime

Calculating a date interval with strtotime()

 
<?php
$birthday = "March 10, 2010";
$whoopee_made = strtotime("$birthday - 9 months ago");
?>

Checking a date range

 
<?
// Get the epoch timestamp for 6 months ago
$range_start = strtotime("6 months ago");
// Get the epoch timestamp for right now
$range_end   = time();
$submitted_date = strtotime($_POST["yr"] . "-" . 
                            $_POST["mo"] . "-" . 
                            $_POST["dy"]);
if (($range_start > $submitted_date) || ($range_end < $submitted_date)) {
    $errors[] = "Please choose a date less than six months old.";
}
?>

Finding the Date for a Weekday

 
<?php
  echo "Today is " . date("d M Y") . ".";
  
  for($i = 1; $i <= 12; $i++)
  {
    $nextmonth = date("Y-" . (date("n") + $i) . "-01");
    $nextmonth_ts = strtotime($nextmonth);
    $firsttue_ts = strtotime("Tuesday", $nextmonth_ts);
    
    echo "<br />The first Tuesday of " . date("F", $firsttue_ts) 
      . " is " . date("d M Y", $firsttue_ts) . ".";
  }
?>

Find the First monday on or after November 1, 2008

 
<?
$monday = strtotime("Monday", $november);
?>

Find weekday

 
<?php
  function find_weekday($month, $year, $weekday, $offset=1)
  {
    $month_ts = strtotime("$year-$month-01");
    if(--$offset > 0)
      $month_ts = strtotime("+$offset week", $month_ts);
    $month_ts = strtotime($weekday, $month_ts);
    return $month_ts;
  }
  echo date("d M Y", find_weekday(5, 2000, "Friday")) . "<br />";
  echo date("d M Y", find_weekday(5, 2000, "Friday", 1)) . "<br />";
  echo date("d M Y", find_weekday(5, 2000, "Fri", 2)) . "<br />";
  echo date("d M Y", find_weekday(5, 2000, "Friday", 3)) . "<br />";
  echo date("d M Y", find_weekday(5, 2000, "Friday", 4));
?>

Getting the Day and Week of the Year

 
<?php 
$mydates = array("2010-01-01", "2010-06-30", "2010-12-31"); 
foreach($mydates as $mydate) { 
    $ts = strtotime($mydate); 
    echo "Day " . date("d M Y: z", $ts) . "<br />\n"; 
} 
?>

If PHP is unable to convert your string into a timestamp, it will return -1.

 
<?
    $mydate = strtotime("Christmas 1979");
    if ($mydate == -1) {
            print "Date conversion failed!";
    } else {
            print "Date conversion succeeded!";
    }
?>

int strtotime ( string time [, int now] ) converts strings to a timestamp

 
<?
    print strtotime("22nd December 1979");
    print strtotime("22 Dec. 1979 17:30");
    print strtotime("1979/12/22");
?>

Obtaining the Difference Between Two Dates

 
<?php
  $date1 = "14 Jun 2002";
  $date2 = "05 Feb 2006";
  $ts1 = strtotime($date1);
  $ts2 = strtotime($date2);
  printf("<p>The difference between %s and %s is %d seconds.<p>\n",
          $date1, $date2, $ts2 - $ts1);
?>

Subtracts a year from a given timestamp

 
<?
    print strtotime("1 year ago", 123456789);
?>

Using strtotime()

 
<?
$now = time();
$later = strtotime("Thursday",$now);
$before = strtotime("last thursday",$now);
print strftime("now: %c \n", $now);
print strftime("later: %c \n", $later);
print strftime("before: %c \n", $before);
?>

Using strtotime() with a starting epoch timestamp

 
<?
$november = mktime(0,0,0,11,1,2008);
?>