Data::Page(3)						User Contributed Perl Documentation					     Data::Page(3)

NAME

       Data::Page - help when paging through sets of results

SYNOPSIS

	 use Data::Page;

	 my $page = Data::Page->new();
	 $page->total_entries($total_entries);
	 $page->entries_per_page($entries_per_page);
	 $page->current_page($current_page);

	 print "	 First page: ", $page->first_page, "
";
	 print "	  Last page: ", $page->last_page, "
";
	 print "First entry on page: ", $page->first, "
";
	 print " Last entry on page: ", $page->last, "
";

DESCRIPTION

       When searching through large amounts of data, it is often the case that a result set is returned that is larger than we want to display on
       one page. This results in wanting to page through various pages of data. The maths behind this is unfortunately fiddly, hence this module.

       The main concept is that you pass in the number of total entries, the number of entries per page, and the current page number. You can then
       call methods to find out how many pages of information there are, and what number the first and last entries on the current page really
       are.

       For example, say we wished to page through the integers from 1 to 100 with 20 entries per page. The first page would consist of 1-20, the
       second page from 21-40, the third page from 41-60, the fourth page from 61-80 and the fifth page from 81-100. This module would help you
       work this out.

METHODS

   new
       This is the constructor, which takes no arguments.

	 my $page = Data::Page->new();

       There is also an old, deprecated constructor, which currently takes two mandatory arguments, the total number of entries and the number of
       entries per page. It also optionally takes the current page number:

	 my $page = Data::Page->new($total_entries, $entries_per_page, $current_page);

   total_entries
       This method get or sets the total number of entries:

	 print "Entries:", $page->total_entries, "
";

   entries_per_page
       This method gets or sets the total number of entries per page (which defaults to 10):

	 print "Per page:", $page->entries_per_page, "
";

   current_page
       This method gets or sets the current page number (which defaults to 1):

	 print "Page: ", $page->current_page, "
";

   entries_on_this_page
       This methods returns the number of entries on the current page:

	 print "There are ", $page->entries_on_this_page, " entries displayed
";

   first_page
       This method returns the first page. This is put in for reasons of symmetry with last_page, as it always returns 1:

	 print "Pages range from: ", $page->first_page, "
";

   last_page
       This method returns the total number of pages of information:

	 print "Pages range to: ", $page->last_page, "
";

   first
       This method returns the number of the first entry on the current page:

	 print "Showing entries from: ", $page->first, "
";

   last
       This method returns the number of the last entry on the current page:

	 print "Showing entries to: ", $page->last, "
";

   previous_page
       This method returns the previous page number, if one exists. Otherwise it returns undefined:

	 if ($page->previous_page) {
	   print "Previous page number: ", $page->previous_page, "
";
	 }

   next_page
       This method returns the next page number, if one exists. Otherwise it returns undefined:

	 if ($page->next_page) {
	   print "Next page number: ", $page->next_page, "
";
	 }

   splice
       This method takes in a listref, and returns only the values which are on the current page:

	 @visible_holidays = $page->splice(@holidays);

   skipped
       This method is useful paging through data in a database using SQL LIMIT clauses. It is simply $page->first - 1:

	 $sth = $dbh->prepare(
	   q{SELECT * FROM table ORDER BY rec_date LIMIT ?, ?}
	 );
	 $sth->execute($page->skipped, $page->entries_per_page);

   change_entries_per_page
       This method changes the number of entries per page and the current page number such that the first item on the current page will be present
       on the new page.

	$page->total_entries(50);
	$page->entries_per_page(20);
	$page->current_page(3);
	print $page->first; # 41
	$page->change_entries_per_page(30);
	print $page->current_page; # 2 - the page that item 41 will show in

NOTES

       It has been said before that this code is "too simple" for CPAN, but I must disagree. I have seen people write this kind of code over and
       over again and they always get it wrong. Perhaps now they will spend more time getting the rest of their code right...

SEE ALSO

       Related modules which may be of interest: Data::Pageset, Data::Page::Tied, Data::SpreadPagination.

AUTHOR

       Based on code originally by Leo Lapworth, with many changes added by by Leon Brocard <acme@astray.com>.

CONTRIBUTORS

       James Laver (ELPENGUIN)

COPYRIGHT

       Copyright (C) 2000-9, Leon Brocard

LICENSE

       This module is free software; you can redistribute it or modify it under the same terms as Perl itself.

perl v5.18.2							    2017-10-06							     Data::Page(3)