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[](https://travis-ci.org/zigorou/p5-iterator-groupedrange)
# NAME
Iterator::GroupedRange - Iterates retrieving a set of specified number rows
# SYNOPSIS
use Iterator::GroupedRange;
my @ds = (
[ 1 .. 6 ],
[ 7 .. 11 ],
[ 11 .. 25 ],
);
my $i1 = Iterator::GroupedRange->new( sub { shift @ds; }, 10 );
$i1->next; # [ 1 .. 10 ]
$i1->next; # [ 11 .. 20 ]
$i1->next; # [ 21 .. 25 ]
my $i2 = Iterator::GroupedRange->new( [ 1 .. 25 ], 10 );
$i2->next; # [ 1 .. 10 ]
$i2->next; # [ 11 .. 20 ]
$i2->next; # [ 21 .. 25 ]
# DESCRIPTION
Iterator::GroupedRange is module to iterate retrieving a set of specified number rows.
Code reference or list reference becomes provider of sets.
It accepts other iterator to get rows, or list.
# METHODS
## new( \\&provider\[, $range, \\%opts\] )
## new( \\@list\[, $range, \\%opts\] )
Return new instance. Arguments details are:
- &provider
The code reference must be taking a list reference or undef.
If the return value is undef or empty array reference, [#has\_next()](https://metacpan.org/pod/#has_next\(\)) will return false value.
- @list
This list reference will be code reference that will be return a set of specified number rows.
- $range
Most number of retrieving rows by each iteration. Default value is 1000.
- %opts
- range
Grouped size.
- rows
Number of rows. For example, using [DBI](https://metacpan.org/pod/DBI)'s statement handle:
my $sth = $dbh->prepare('SELECT blah FROM example');
$sth->execute;
my $iter; $iter = Iterator::GroupedRange->new(sub {
if ( my $ids = $sth->fetchrow_arrayref( undef, $iter->range ) ) {
return [ map { $_->[0] } @$ids ];
}
else {
return;
}
}, { rows => $sth->rows, range => 1000 });
## has\_next()
Return which the iterator has next rows or not.
## next()
Return next rows.
## is\_last()
Return which the iterator becomes ended of iteration or not.
## append(@items)
## append(\\@items)
Append new items.
## range()
Return grouped size.
## rows()
Return total rows.
# AUTHOR
Toru Yamaguchi
# SEE ALSO
- [List::MoreUtils](https://metacpan.org/pod/List::MoreUtils)
[List::MoreUtils](https://metacpan.org/pod/List::MoreUtils) has `natatime` subroutine looks like this module.
The `natatime` subroutine can treat only list.
- [DBI](https://metacpan.org/pod/DBI)
[DBI](https://metacpan.org/pod/DBI)'s fetchall\_arrayref can accepts max\_rows argument.
This feature is similar to this module. For example:
use DBI;
use Data::Dumper;
my $sth = $dbh->prepare('SELECT id FROM people');
while ( my $ids = $sth->fetchall_arrayref(undef, 100) ) {
$ids = [ map { $_->[0] } @$ids ];
warn Dumper($ids);
}
# LICENSE
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
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