| Subject: | part_implicitly |
Given:
@list =
part_implicitly { $_->[0] }
(
[qw<A 1 2 3>],
[qw<A 4 5 6>],
[qw<B 1 2 3>],
[qw<A 7 8 9>],
);
Then @list should be:
(
[
[qw<A 1 2 3>],
[qw<A 4 5 6>],
],
[
[qw<B 1 2 3>],
],
[
[qw<A 7 8 9>],
],
);
That is, "part_implicitly" partitions the list like "part" does, but
rather than the block returning a number indicating the partition, it
returns a value which "part_implicitly" remembers. When the value
changes from the last execution, then a new partition is started.
An example of using "part" to perform this task can be seen here:
http://www.perlmonks.org/?node_id=973569
This block:
part {
state $part = 0;
state $last = undef;
$part++ if defined $last && $last ne $_->[0];
$last = $_->[0];
$part
}
Could be replaced with this:
part_implicitly { $_->[0] }