Supported Date and Time Formats
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Relative Formats

Used Symbols
Description Format
dayname 'sunday' | 'monday' | 'tuesday' | 'wednesday' | 'thursday' | 'friday' | 'saturday' | 'sun' | 'mon' | 'tue' | 'wed' | 'thu' | 'fri' | 'sat' | 'sun'
daytext 'weekday' | 'weekdays'
number [+-]?[0-9]+
ordinal 'first' | 'second' | 'third' | 'fourth' | 'fifth' | 'sixth' | 'seventh' | 'eighth' | 'ninth' | 'tenth' | 'eleventh' | 'twelfth' | 'next' | 'last' | 'previous' | 'this'
reltext 'next' | 'last' | 'previous' | 'this'
space [ \t]+
unit (('sec' | 'second' | 'min' | 'minute' | 'hour' | 'day' | 'fortnight' | 'forthnight' | 'month' | 'year') 's'?) | 'weeks' | daytext
Day-based Notations
Format Description Examples
'yesterday' Midnight of yesterday "yesterday 14:00"
'midnight' The time is set to 00:00:00  
'today' The time is set to 00:00:00  
'now' Now - this is simply ignored  
'noon' The time is set to 12:00:00 "yesterday noon"
'tomorrow' Midnight of tomorrow  
'back of' hour 15 minutes past the specified hour "back of 7pm", "back of 15"
'front of' hour 15 minutes before the specified hour "front of 5am", "front of 23"
'first day' ' of'? Sets the day of the first of the current month. This phrase is best used together with a month name following it. "first day of January 2008"
'last day' ' of'? Sets the day to the last day of the current month. This phrase is best used together with a month name following it. "last day of next month"
ordinal space dayname space 'of' Calculates the x-th week day of the current month. "first sat of July 2008"
'last' space dayname space 'of' Calculates the last week day of the current month. "last sat of July 2008"
number space? (unit | 'week') Handles relative time items where the value is a number. "+5 weeks", "12 day", "-7 weekdays"
ordinal space unit Handles relative time items where the value is text. "fifth day", "second month"
'ago' Negates all the values of previously found relative time items. "2 days ago", "8 days ago 14:00", "2 months 5 days ago", "2 months ago 5 days", "2 days ago ago"
dayname Moves to the next day of this name. "Monday"
reltext space 'week' Handles the special format "weekday + last/this/next week". "Monday next week"

Note:

Relative statements are always processed after non-relative statements. This makes "+1 week july 2008" and "july 2008 +1 week" equivalent.

Exceptions to this rule are: "yesterday", "midnight", "today", "noon" and "tomorrow". Note that "tomorrow 11:00" and "11:00 tomorrow" are different. Considering today's date of "July 23rd, 2008" the first one produces "2008-07-24 11:00" where as the second one produces "2008-07-24 00:00". The reason for this is that those five statements directly influence the current time.

Note:

Observe the following remarks when the current day-of-week is the same as the day-of-week used in the date/time string. The current day-of-week could have been (re-)calculated by non-relative parts of the date/time string however.

  1. "dayname" does not advance to another day. (Example: "Wed July 23rd, 2008" means "2008-07-23").
  2. "number dayname" does not advance to another day. (Example: "1 wednesday july 23rd, 2008" means "2008-07-23").
  3. "number week dayname" will first add the number of weeks, but does not advance to another day. In this case "number week" and "dayname" are two distinct blocks. (Example: "+1 week wednesday july 23rd, 2008" means "2008-07-30").
  4. "ordinal dayname" does advance to another day. (Example "first wednesday july 23rd, 2008" means "2008-07-30").
  5. "number week ordinal dayname" will first add the number of weeks, and then advances to another day. In this case "number week" and "ordinal dayname" are two distinct blocks. (Example: "+1 week first wednesday july 23rd, 2008" means "2008-08-06").
  6. "ordinal dayname 'of' " does not advance to another day. (Example: "first wednesday of july 23rd, 2008" means "2008-07-02" because the specific phrase with 'of' resets the day-of-month to '1' and the '23rd' is ignored here).

Also observe that the "of" in "ordinal space dayname space 'of' " and "'last' space dayname space 'of' " does something special.

  1. It sets the day-of-month to 1.
  2. "ordinal dayname 'of' " does not advance to another day. (Example: "first tuesday of july 2008" means "2008-07-01").
  3. "ordinal dayname " does advance to another day. (Example: "first tuesday july 2008" means "2008-07-08", see also point 4 in the list above).
  4. "'last' dayname 'of' " takes the last dayname of the current month. (Example: "last wed of july 2008" means "2008-07-30")
  5. "'last' dayname" takes the last dayname from the current day. (Example: "last wed july 2008" means "2008-06-25"; "july 2008" first sets the current date to "2008-07-01" and then "last wed" moves to the previous Wednesday which is "2008-06-25").

Note:

Relative month values are calculated based on the length of months that they pass through. An example would be "+2 month 2011-11-30", which would produce "2012-01-30". This is due to November being 30 days in length, and December being 31 days in length, producing a total of 61 days.

Supported Date and Time Formats
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PHP手册 - N: Relative Formats

用户评论:

scragar at gmail dot com (09-Nov-2011 04:04)

Just for those who want the last day of the year without calling the function twice:

<?php
echo date('Y-m-d',
    strToTime('1/1 next year -1 day')
);
//   2011-12-31
?>

For reference this is actually saying "Take the first day of the first month next year, then subtract 1 day".

matt (14-Sep-2011 10:23)

If the ordinal being used is "last" and the next month is n, use the "n 1". Otherwise, if the previous month is p and it has d number of days in it, use "p d".

For example: "last thursday of November" becomes "last thursday December 1" and "fourth thursday of November" becomes "fourth thursday September 30th"

Hopes this helps someone out there.

erwin at darcoury dot nl (01-Jun-2011 02:39)

In PHP 5.2, "first monday of may 2011" is invalid, but "first monday may 2011" does work. Simply omit "of" if above examples do not work.

geneticdrift (31-Mar-2011 06:50)

Month skipping has issues with number of days in the month.

'+1 month' may move to the following month if the next month has less days than the current:

<?php print date('d M Y H:i:s', strtotime('+1 month', strtotime('Thu Mar 31 19:50:41 IST 2011'))); ?>
Prints: 01 May 2011 19:50:41

But with 'last day of +1 month' the result is different:

<?php print date('d M Y H:i:s', strtotime('last day of +1 month', strtotime('Thu Mar 31 19:50:41 IST 2011'))); ?>
Prints: 30 Apr 2011 19:50:41

(PHP 5.3.3)

lcampanis (17-Mar-2011 12:34)

To get the last day of the previous month use:
<?php
date("Y-m-t", strtotime("last month"));
?>

Note 't' instead of 'd'

Vadim Pronin (16-Mar-2011 11:00)

Note that '-1 month' may produce unexpected result when used in last day of month that has 31 days:

strtotime('31 march 2011 -1 month')
returns 03 march 2011

tripollite at gmail dot com (04-Jan-2011 11:59)

strtotime('last day of this year') doesn't work because last day of is only for month

use strtotime('-1 day', strtotime('first day of next year')) or anything else

e dot sand at elisand dot com (20-Jul-2010 10:21)

It should be noted that apparently some of these strings only work in PHP 5.3 apparently, notably:

"first day of this month" and "last day of this month" for example.  According to information found on another website, the "xxx day of" feature was added in PHP 5.3.