Data::Page(3pm)

1Data::Page(3)         User Contributed Perl Documentation        Data::Page(3)
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NAME

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

9         use Data::Page;
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11         my $page = Data::Page->new();
12         $page->total_entries($total_entries);
13         $page->entries_per_page($entries_per_page);
14         $page->current_page($current_page);
15
16         print "         First page: ", $page->first_page, "\n";
17         print "          Last page: ", $page->last_page, "\n";
18         print "First entry on page: ", $page->first, "\n";
19         print " Last entry on page: ", $page->last, "\n";
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DESCRIPTION

22       When searching through large amounts of data, it is often the case that
23       a result set is returned that is larger than we want to display on one
24       page. This results in wanting to page through various pages of data.
25       The maths behind this is unfortunately fiddly, hence this module.
26
27       The main concept is that you pass in the number of total entries, the
28       number of entries per page, and the current page number. You can then
29       call methods to find out how many pages of information there are, and
30       what number the first and last entries on the current page really are.
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32       For example, say we wished to page through the integers from 1 to 100
33       with 20 entries per page. The first page would consist of 1-20, the
34       second page from 21-40, the third page from 41-60, the fourth page from
35       61-80 and the fifth page from 81-100. This module would help you work
36       this out.
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METHODS

39   new
40       This is the constructor, which takes no arguments.
41
42         my $page = Data::Page->new();
43
44       There is also an old, deprecated constructor, which currently takes two
45       mandatory arguments, the total number of entries and the number of
46       entries per page. It also optionally takes the current page number:
47
48         my $page = Data::Page->new($total_entries, $entries_per_page, $current_page);
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50   total_entries
51       This method get or sets the total number of entries:
52
53         print "Entries:", $page->total_entries, "\n";
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55   entries_per_page
56       This method gets or sets the total number of entries per page (which
57       defaults to 10):
58
59         print "Per page:", $page->entries_per_page, "\n";
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61   current_page
62       This method gets or sets the current page number (which defaults to 1):
63
64         print "Page: ", $page->current_page, "\n";
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66   entries_on_this_page
67       This methods returns the number of entries on the current page:
68
69         print "There are ", $page->entries_on_this_page, " entries displayed\n";
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71   first_page
72       This method returns the first page. This is put in for reasons of
73       symmetry with last_page, as it always returns 1:
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75         print "Pages range from: ", $page->first_page, "\n";
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77   last_page
78       This method returns the total number of pages of information:
79
80         print "Pages range to: ", $page->last_page, "\n";
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82   first
83       This method returns the number of the first entry on the current page:
84
85         print "Showing entries from: ", $page->first, "\n";
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87   last
88       This method returns the number of the last entry on the current page:
89
90         print "Showing entries to: ", $page->last, "\n";
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92   previous_page
93       This method returns the previous page number, if one exists. Otherwise
94       it returns undefined:
95
96         if ($page->previous_page) {
97           print "Previous page number: ", $page->previous_page, "\n";
98         }
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100   next_page
101       This method returns the next page number, if one exists. Otherwise it
102       returns undefined:
103
104         if ($page->next_page) {
105           print "Next page number: ", $page->next_page, "\n";
106         }
107
108   splice
109       This method takes in a listref, and returns only the values which are
110       on the current page:
111
112         @visible_holidays = $page->splice(\@holidays);
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114   skipped
115       This method is useful paging through data in a database using SQL LIMIT
116       clauses. It is simply $page->first - 1:
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118         $sth = $dbh->prepare(
119           q{SELECT * FROM table ORDER BY rec_date LIMIT ?, ?}
120         );
121         $sth->execute($page->skipped, $page->entries_per_page);
122
123   change_entries_per_page
124       This method changes the number of entries per page and the current page
125       number such that the first item on the current page will be present on
126       the new page.
127
128        $page->total_entries(50);
129        $page->entries_per_page(20);
130        $page->current_page(3);
131        print $page->first; # 41
132        $page->change_entries_per_page(30);
133        print $page->current_page; # 2 - the page that item 41 will show in
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NOTES

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

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

150       James Laver (ELPENGUIN)
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COPYRIGHT

153       Copyright (C) 2000-9, Leon Brocard
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LICENSE

156       This module is free software; you can redistribute it or modify it
157       under the same terms as Perl itself.
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161perl v5.32.0                      2020-07-28                     Data::Page(3)