从存储在另一个动态变量中的日期中减去动态值

I need to subtract a number of days from a date which is stored in a dynamic variable '$workdate' .

The number of days to be subtracted from the date is also generating dynamically.

$workdate=date('d/m/y', strtotime($wdate)); //$wdate is a date selected from date picker and passed from previous page.

I have a variable named '$deduc' whose value is dynamically generating. suppose $deduc=2 now I need to do:

$workdate-$deduc=?

$workdate=date('d/m/y', strtotime($wdate));

while($some_value=0)
{
  $deduc=$deduc+1;
  $some_value--;

}

now I need to subtract $deduc no. of days from $workdate. Please do help.

Just create a DateTime object with DateTime::createFromFormat() and modify() your date, e.g.

$date = DateTime::createFromFormat("d/m/y", $workdate);
echo $date->modify("- $deduc days")->format('Y-m-d');

Demo

Take a look at the DateTime class and especially at the DateTime::sub() method.