In PHP, how to know how many mondays have passed in this month uptil today?

问题

Assume today is Feb 21, 2011 ( Monday ). It is the third Monday of this month. If date is given as input, How can I know how many Mondays have passed before it?

回答1:

$now=time() + 86400;
if (($dow = date('w', $now)) == 0) $dow = 7; 
$begin = $now - (86400 * ($dow-1));

echo "Mondays: ".ceil(date('d', $begin) / 7)."<br/>";

works for me....

EDIT: includes today's monday too

回答2:

That sounds like a pretty straightforward division calculation. From the current date, subtract number of days past last monday (example: wednesday = -2), divide it by 7 and ceil() it to round it up.

EDIT: That will include the current monday in the number, returning "3" for monday 21st.

回答3:

    <?php

 function mondays_get($month, $stop_if_today = true) {

$timestamp_now = time();

for($a = 1; $a < 32; $a++) {

    $day = strlen($a) == 1 ? "0".$a : $a;
    $timestamp = strtotime($month . "-$day");
    $day_code = date("w", $timestamp);
    if($timestamp > $timestamp_now)
        break;
    if($day_code == 1)
        @$mondays++;

}

return $mondays;
}

echo mondays_get('2011-02');

Hope this is of use to you! i've just rolled it up.

"Beware of bugs in the above code; I have only proved it correct, not tried it."

Works OK afaik

回答4:

You could loop through all the days until now and count the mondays:

$firstDate = mktime(0, 0, 0, date("n"), 1, date("Y"));
$now = time();
$mondays = 0;
for ($i = $firstDate; $i < $now; $i = $i + 24*3600) {
    if (date("D", $i) == "Mon")
        $mondays ++;
}

Haven't tested this script

回答5:

Try this...

//find the most recent monday (doesn't find today if today is Monday though)
$startDate = strtotime( 'last monday' );

//if 'last monday' was not this month, 0 mondays.  
//if 'last monday' was this month, count the weeks
$mondays = date( 'm', $startDate ) != date( 'm' ) 
         ? 0 
         : floor( date( 'd', $startDate ) / 7 );

//increment the count if today is a monday (since strtotime didn't find it)
if ( date( 'w' ) == 1 ) $mondays++;

回答6:

Another way is to find what day of the week is today, find the first such day of the month via some magic strtotime(), then calculate the difference between that and now in weeks. See below for a function that will take a Y-m-d formatted date() and return which weekday of the month it is.

Note: strtotime needs to be verbose, including "of" and the month: "first Monday of 2011-02" otherwise it advances one day. This bit me when I was testing edge cases.

Also added some display pepper which is completely optional but I felt like it.

function nthWeekdayOfMonth($day) {

    $dayTS = strtotime($day) ;

    $dayOfWeekToday = date('l', $dayTS) ;

    $firstOfMonth = date('Y-m', $dayTS) . "-01" ;
    $firstOfMonthTS = strtotime($firstOfMonth) ;

    $firstWhat = date('Y-m-d', strtotime("first $dayOfWeekToday of $monthYear", $firstOfMonthTS)) ;
    $firstWhatTS = strtotime($firstWhat) ;

    $diffTS = $dayTS - $firstWhatTS ;
    $diffWeeks = $diffTS / (86400 * 7);

    $nthWeekdayOfMonth = $diffWeeks + 1;

    return $nthWeekdayOfMonth ;
}

$day = date('Y-m-d') ;
$nthWeekdayOfMonth = nthWeekdayOfMonth($day) ;

switch ($nthWeekdayOfMonth) {
    case 1: 
        $inflector = "st" ;
        break ;
    case 2: 
        $inflector = "nd" ;
        break ;
    case 3: 
        $inflector = "rd" ;
        break ;
    default:
        $inflector = "th" ;
}

$dayTS = strtotime($day) ;

$monthName = date('F', $dayTS) ;    
$dayOfWeekToday = date('l', $dayTS) ;

echo "Today is the {$nthWeekdayOfMonth}$inflector $dayOfWeekToday in $monthName" ;

来源：https://stackoverflow.com/questions/5069966/in-php-how-to-know-how-many-mondays-have-passed-in-this-month-uptil-today

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date

recurrence