Catmandu::Iterable - Base class for all iterable Catmandu classes
# Create an example Iterable using the Catmandu::Importer::Mock class my $it = Catmandu::Importer::Mock->new(size => 10); my $array_ref = $it->to_array; my $num = $it->count; # Loop functions $it->each(sub { print shift->{n} }); my $item = $it->first; $it->rest ->each(sub { print shift->{n} }); $it->slice(3,2) ->each(sub { print shift->{n} }); $it->take(5) ->each(sub { print shift->{n} }); $it->group(5) ->each(sub { printf "group of %d items\n" , shift->count}); $it->tap(\&logme)->tap(\&printme)->tap(\&mailme) ->each(sub { print shift->{n} }); # Select and loop my $item = $it->detect(sub { shift->{n} > 5 }); $it->select(sub { shift->{n} > 5}) ->each(sub { print shift->{n} }); $it->reject(sub { shift->{n} > 5}) ->each(sub { print shift->{n} }); # Boolean if ($it->any(sub { shift->{n} > 5}) { .. at least one n > 5 .. } if ($it->many(sub { shift->{n} > 5}) { .. at least two n > 5 .. } if ($it->all(sub { shift->{n} > 5}) { .. all n > 5 .. } # Modify and summary my $it2 = $it->map(sub { shift->{n} * 2 }); my $sum = $it2->reduce(0,sub { my ($prev,$this) = @_; $prev + $this; }); my $it3 = $it->group(2)->invoke('to_array');
The Catmandu::Iterable class provides many list methods to Iterators such as Importers and Exporters. Most of the methods are lazy if the underlying datastream supports it. Beware of idempotence: many iterators contain state information and calls will give different results on a second invocation.
Return all the items in the Iterator as an ARRAY ref.
Return the count of all the items in the Iterator.
For each item in the Iterator execute the callback function with the item as first argument. Returns the number of items in the Iterator.
Return the first item from the Iterator.
Returns an Iterator containing everything except the first item.
Returns an Iterator starting at the item at INDEX returning at most LENGTH results.
Returns an Iterator with the first NUM results.
Splitting the Iterator into NUM parts and returning an Iterator for each part.
Returns an Iterator which returns the first item of each iterator then the second of each and so on.
Alias for includes.
includes
return true if any item in the collection is deeply equal to $data.
$data
Returns a copy of the Iterator and executing callback on each item. This method works like the Unix tee command. Use this command to peek into an iterable while it is processing results. E.g. you are writing code to process an iterable and wrote something like:
$it->each(sub { # Very complicated routine .... });
Now you would like to benchmark this piece of code (how fast are we processing). This can be done by tapping into the iterator and calling a 'benchmark' subroutine in your program that for instance counts the number of items divided by the execution time.
$it->tap(\&benchmark)->each(sub { # Very complicated routine .... }); sub benchmark { my $item = shift; $start ||= time; $count++; printf "%d recs/sec\n" , $count/(time - $start + 1) if $count % 100 == 0; }
Returns the first item for which callback returns a true value.
If the iterator contains STRING values, then return the first item which matches the regex.
If the iterator contains HASH values, then return the first item where the value of $key is equal to val.
If the iterator contains HASH values, then return the first item where the value of $key matches the regex.
If the iterator contains HASH values, then return the first item where the value of $key is equal to any of the vals given.
Returns an Iterator for each item for which callback returns a true value.
If the iterator contains STRING values, then return each item which matches the regex.
If the iterator contains HASH values, then return each item where the value of $key is equal to val.
If the iterator contains HASH values, then return each item where the value of $key matches the regex.
If the iterator contains HASH values, then return each item where the value of $key is equal to any of the vals given.
Returns an Iterator for each item for which callback returns a false value.
If the iterator contains STRING values, then reject every item except those matching the regex.
If the iterator contains HASH values, then reject every item for where the value of $key DOESN'T match the regex.
If the iterator contains HASH values, then return each item where the value of $key is NOT equal to val.
If the iterator contains HASH values, then return each item where the value of $key is NOT equal to any of the vals given.
Returns true if at least one item generates a true value when executing callback.
Alias for many.
many
Returns true if at least two items generate a true value when executing callback.
Returns true if all the items generate a true value when executing callback.
Returns a new Iterator containing for each item the result of the callback.
Alias for reduce.
reduce
For each item in the Iterator execute &callback($prev,$item) where $prev is the option START value or the result of the previous call to callback. Returns the final result of the callback function.
This is a shortcut for $it->map(sub { $_[0]->NAME }).
Catmandu::Iterator.
To install Catmandu, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Catmandu
CPAN shell
perl -MCPAN -e shell install Catmandu
For more information on module installation, please visit the detailed CPAN module installation guide.