php gets the number of days in a month

Given a month, it is required to return how many days there are in this month.

There are many ways. The first one uses the built-in function

cal_days_in_month：Return The number of days in a certain month in a certain year in a certain calendar (recommended learning: PHP Programming from Beginner to Mastery)

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

calendar: Calendar used for calculation

month: Select a certain month in the calendar

year: Select a certain year in the calendar

The cal_day_in_month function needs to be compiled with --enable-calendar before PHP can be used

The second type is a custom function that uses the year and month to determine how many days there are in a month.

function get_day( $date )   
{
    $tem = explode('/' , $date);       //切割日期  得到年份和月份
    $year = $tem['0'];
    $month = $tem['1'];
    if( in_array($month , array( 1 , 3 , 5 , 7 , 8 , 01 , 03 , 05 , 07 , 08 , 10 , 12)))
    {
        $text = $year.'年的'.$month.'月有31天';
    }
    elseif( $month == 2 )
    {
        if ( $year%400 == 0  || ($year%4 == 0 && $year%100 !== 0) )        //判断是否是闰年
        {
            $text = $year.'年的'.$month.'月有29天';
        }
        else{
            $text = $year.'年的'.$month.'月有28天';
        }
    }
    else{
        $text = $year.'年的'.$month.'月有30天';
    }
    return $text;
}

$i=2;
$y=2013;
echo get_day($y.'/'.$i);

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