Question

I have been using the following code for the last few months, which loops through a period of months from a predefined date until it gets to today’s date.

use Date::Pcalc qw(:all);

$startDay = 1;
$startMonth = '4';
$startYear = '2009';

$dateToday = `date +%Y-%m-%d`;
($yt,$mt,$dt) = split(/\-/,$dateToday);

while ($endMonth <= $mt || $startYear < $yt ) {

if ($startMonth eq '12') {
    $endMonth = 1;
    $endYear = $startYear + 1;
  } else {
    $endMonth = $startMonth + 1;
    $endYear = $startYear;
  }

  if ($startMonth eq '12') {
    $endYear = $startYear + 1;
  }

  ($meYear,$meMonth,$meDay) = Add_Delta_Days($endYear,$endMonth,$startDay,-1);
  $endOfMonth = "$meYear-$meMonth-$meDay";
  $monthText = Month_to_Text($startMonth);

  $startDate = "$startYear-$startMonth-1";
  $endDate = "$endYear-$endMonth-1";

print "$startDate - $endDate\n";

if ($startMonth eq '12') {
    $startMonth = 1;
    $startYear++;
  } else {
    $startMonth++
  }

}

This has been working great for the last few months, but I’ve realised that now in December, as $endmonth will never be greater $mt (12), this causes an infinite loop.

I’ve not been able to figure out any alternate way of doing this. I feel like I should be able to fix this relatively easily but I seem to be having severe ‘developer’s block’

Thanks in advance to anyone who can assist.

Answer 1

I think you have a couple of problems with your code. But lets get to the first problem which is the enddate in month 12 which causes a loop in this statement:

    while ($endMonth <= $mt || $startYear < $yt ) {

OK what you should do is something like this, once you have the current date, year month and day. You will notice that others have suggested different way to get the current date You should take up this suggestion. However once you have the date this code below should be adopted:

    ($yt,$mt,$dt) = split(/\-/,$dateToday);
    # the line below will create a date like 201212 (yyyy mm) but if the month is a 1 digit month it will place a 0 in front of it to ensure your yymm variable always holds 6 characters in the format of yyyy mm - ok
    my $yymm = $yt . ${\(length($mt) == 1 ? '0' : '')} . $mt;
    # Now lets check the end date against the yymm
    # initialise end date as end_yymm - again it inserts a 0 for single digit month
    my $end_yymm = $startyear . ${\(length($startMonth) == 1 ? '0' : '')} . $startMonth;
    # the above should get the date as '200904' from your code provide
    # the while will check end_yymm like 200904 < 201212 - yes it is...
    ## the end_yymm will keep getting incremented each month and so will the year component at the end of each year until it reaches 201212
    ## then the question 201212 < 201212 will cause the while to end
    ## If you want it go into 201301 then say while ($end_yymm <= $yymm) {
    ## Hope you get the picture
    while ($end_yymm < $yymm) {

    if ($startMonth eq '12') {
        $endMonth = 1;
        $endYear = $startYear + 1;
    } else {
      $endMonth = $startMonth + 1;
      $endYear = $startYear;
    }

    ## Now this one seems to be repeating the endYear calculation as above - to me it seems redundant - maybe get rid of it
    if ($startMonth eq '12') {
       $endYear = $startYear + 1;
    }        

    ## Now that you have the end year and month incremented setup the end_yymm variable again to be picked up in the while statement:
    $end_yymm = $startyear . ${\(length($startMonth) == 1 ? '0' : '')} . $startMonth;

     # ...... carry on with the rest of your code

    } # end the while loop

And that should do it.

All the best