Mojo::Collection(3)

NAME
Mojo::Collection - Collection

SYNOPSIS
  use Mojo::Collection;

  # Manipulate collection
  my $collection = Mojo::Collection->new(qw(just works));
  unshift @$collection, 'it';
  say $collection->join("\n");

  # Chain methods
  $collection->map(sub { ucfirst })->shuffle->each(sub ($word, $num) {
    say "$num: $word";
  });

  # Use the alternative constructor
  use Mojo::Collection qw(c);
  c(qw(a b c))->join('/')->url_escape->say;

DESCRIPTION
Mojo::Collection is an array-based container for collections.

  # Access array directly to manipulate collection
  my $collection = Mojo::Collection->new(1 .. 25);
  $collection->[23] += 100;
  say for @$collection;

FUNCTIONS
Mojo::Collection implements the following functions, which can be imported individually.

  c
  my $collection = c(1, 2, 3);

Construct a new array-based Mojo::Collection object.

METHODS
Mojo::Collection implements the following methods.

  TO_JSON
  my $array = $collection->TO_JSON;

Alias for "to_array".

  compact
  my $new = $collection->compact;

Create a new collection with all elements that are defined and not an empty string.

  # "0, 1, 2, 3"
  c(0, 1, undef, 2, '', 3)->compact->join(', ');

  each
  my @elements = $collection->each;
  $collection  = $collection->each(sub {...});

Evaluate callback for each element in collection, or return all elements as a list if none has been provided. The element will be the first argument passed to the callback, and is also available as $_.

  # Make a numbered list
  $collection->each(sub ($e, $num) {
    say "$num: $e";
  });

  first
  my $first = $collection->first;
  my $first = $collection->first(qr/foo/);
  my $first = $collection->first(sub {...});
  my $first = $collection->first('some_method');
  my $first = $collection->first('some_method', @args);

Evaluate regular expression/callback for, or call method on, each element in collection and return the first one that matched the regular expression, or for which the callback/method returned true. The element will be the first argument passed to the callback, and is also available as $_.

  # Longer version
  my $first = $collection->first(sub { $_->some_method(@args) });

  # Find first value that contains the word "mojo"
  my $interesting = $collection->first(qr/mojo/i);

  # Find first value that is greater than 5
  my $greater = $collection->first(sub { $_ > 5 });

  flatten
  my $new = $collection->flatten;

Flatten nested collections/arrays recursively and create a new collection with all elements.

  # "1, 2, 3, 4, 5, 6, 7"
  c(1, [2, [3, 4], 5, [6]], 7)->flatten->join(', ');

  grep
  my $new = $collection->grep(qr/foo/);
  my $new = $collection->grep(sub {...});
  my $new = $collection->grep('some_method');
  my $new = $collection->grep('some_method', @args);

Evaluate regular expression/callback for, or call method on, each element in collection and create a new collection with all elements that matched the regular expression, or for which the callback/method returned true. The element will be the first argument passed to the callback, and is also available as $_.

  # Longer version
  my $new = $collection->grep(sub { $_->some_method(@args) });

  # Find all values that contain the word "mojo"
  my $interesting = $collection->grep(qr/mojo/i);

  # Find all values that are greater than 5
  my $greater = $collection->grep(sub { $_ > 5 });

  head
  my $new = $collection->head(4);
  my $new = $collection->head(-2);

Create a new collection with up to the specified number of elements from the beginning of the collection. A negative number will count from the end.

  # "A B C"
  c('A', 'B', 'C', 'D', 'E')->head(3)->join(' ');

  # "A B"
  c('A', 'B', 'C', 'D', 'E')->head(-3)->join(' ');

  join
  my $stream = $collection->join;
  my $stream = $collection->join("\n");

Turn collection into Mojo::ByteStream.

  # Join all values with commas
  $collection->join(', ')->say;

  last
  my $last = $collection->last;

Return the last element in collection.

  map
  my $new = $collection->map(sub {...});
  my $new = $collection->map('some_method');
  my $new = $collection->map('some_method', @args);

Evaluate callback for, or call method on, each element in collection and create a new collection from the results. The element will be the first argument passed to the callback, and is also available as $_.

  # Longer version
  my $new = $collection->map(sub { $_->some_method(@args) });

  # Append the word "mojo" to all values
  my $mojoified = $collection->map(sub { $_ . 'mojo' });

  new
  my $collection = Mojo::Collection->new(1, 2, 3);

Construct a new array-based Mojo::Collection object.

  reduce
  my $result = $collection->reduce(sub {...});
  my $result = $collection->reduce(sub {...}, $initial);

Reduce elements in collection with a callback and return its final result, setting $a and $b each time the callback is executed. The first time $a will be set to an optional initial value or the first element in the collection. And from then on $a will be set to the return value of the callback, while $b will always be set to the next element in the collection.

  # Calculate the sum of all values
  my $sum = $collection->reduce(sub { $a + $b });

  # Count how often each value occurs in collection
  my $hash = $collection->reduce(sub { $a->{$b}++; $a }, {});

  reverse
  my $new = $collection->reverse;

Create a new collection with all elements in reverse order.

  shuffle
  my $new = $collection->shuffle;

Create a new collection with all elements in random order.

  size
  my $size = $collection->size;

Number of elements in collection.

  sort
  my $new = $collection->sort;
  my $new = $collection->sort(sub {...});

Sort elements based on return value of a callback and create a new collection from the results, setting $a and $b to the elements being compared, each time the callback is executed.

  # Sort values case-insensitive
  my $case_insensitive = $collection->sort(sub { uc($a) cmp uc($b) });

  tail
  my $new = $collection->tail(4);
  my $new = $collection->tail(-2);

Create a new collection with up to the specified number of elements from the end of the collection. A negative number will count from the beginning.

  # "C D E"
  c('A', 'B', 'C', 'D', 'E')->tail(3)->join(' ');

  # "D E"
  c('A', 'B', 'C', 'D', 'E')->tail(-3)->join(' ');

  tap
  $collection = $collection->tap(sub {...});

Alias for "tap" in Mojo::Base.

  to_array
  my $array = $collection->to_array;

Turn collection into array reference.

  uniq
  my $new = $collection->uniq;
  my $new = $collection->uniq(sub {...});
  my $new = $collection->uniq('some_method');
  my $new = $collection->uniq('some_method', @args);

Create a new collection without duplicate elements, using the string representation of either the elements or the return value of the callback/method to decide uniqueness. Note that "undef" and empty string are treated the same.

  # Longer version
  my $new = $collection->uniq(sub { $_->some_method(@args) });

  # "foo bar baz"
  c('foo', 'bar', 'bar', 'baz')->uniq->join(' ');

  # "[[1, 2], [2, 1]]"
  c([1, 2], [2, 1], [3, 2])->uniq(sub{ $_->[1] })->to_array;

  with_roles
  my $new_class = Mojo::Collection->with_roles('Mojo::Collection::Role::One');
  my $new_class = Mojo::Collection->with_roles('+One', '+Two');
  $collection   = $collection->with_roles('+One', '+Two');

Alias for "with_roles" in Mojo::Base.

SEE ALSO
Mojolicious, Mojolicious::Guides, <https://mojolicious.org>.