In List§

See primary documentation in context for routine pick

multi        pick($count, *@list --> Seq:D)
multi method pick(List:D: $count --> Seq:D)
multi method pick(List:D: --> Mu)
multi method pick(List:D: Callable $calculate --> Seq:D)

If $count is supplied: Returns $count elements chosen at random and without repetition from the invocant. If * is passed as $count, or $count is greater than or equal to the size of the list, then all elements from the invocant list are returned in a random sequence; i.e. they are returned shuffled.

In method form, if $count is omitted: Returns a single random item from the list, or Nil if the list is empty

Examples:

say <a b c d e>.pick;           # OUTPUT: «b␤» 
say <a b c d e>.pick: 3;        # OUTPUT: «(c a e)␤» 
say <a b c d e>.pick: *;        # OUTPUT: «(e d a b c)␤»

As of the 2021.06 release of the Rakudo compiler, it is also possible to specify ** (aka HyperWhatever) as the count.

In that case, .pick will start picking again on the original list after it has been exhausted, again and again, indefinitely.

say <a b c>.pick(**).head(10);  # OUTPUT: «((a c b c a b b c a b))␤»

In role Setty§

See primary documentation in context for method pick

multi method pick($count = 1)

Returns $count elements chosen at random (without repetition) from the set.

If * is passed as $count, or $count is greater than or equal to the size of the set, then all its elements are returned in random order (shuffled).

In enum Bool§

See primary documentation in context for routine pick

multi method pick(Bool:U: --> Bool:D)
multi method pick(Bool:U: $count --> Seq:D)

Returns a random pick of True and/or False.

If it's called without an argument then it returns just one pick:

say Bool.pick;                                    # OUTPUT: «True␤»

If it's called with a $count of one then it returns a Seq with just one pick:

say Bool.pick(1);                                 # OUTPUT: «(False)␤»

If $count is * or greater than or equal to two then it returns a Seq with two elements -- either True then False, or False then True:

say Bool.pick(*);                                 # OUTPUT: «(False True)␤»

In role Baggy§

See primary documentation in context for method pick

multi method pick(Baggy:D: --> Any)
multi method pick(Baggy:D: $count --> Seq:D)

Like an ordinary list pick, but returns keys of the invocant weighted by their values, as if the keys were replicated the number of times indicated by the corresponding value and then list pick used. The underlying metaphor for picking is that you're pulling colored marbles out a bag. (For "picking with replacement" see roll instead). If * is passed as $count, or $count is greater than or equal to the total of the invocant, then total elements from the invocant are returned in a random sequence.

Note that each pick invocation maintains its own private state and has no effect on subsequent pick invocations.

my $breakfast = bag <eggs bacon bacon bacon>;
say $breakfast.pick;                              # OUTPUT: «eggs␤» 
say $breakfast.pick(2);                           # OUTPUT: «(eggs bacon)␤» 
 
say $breakfast.total;                             # OUTPUT: «4␤» 
say $breakfast.pick(*);                           # OUTPUT: «(bacon bacon bacon eggs)␤»

In role Mixy§

See primary documentation in context for method pick

method pick($?)

Throws an exception. The feature is not supported on the type, since there's no clear value to subtract from non-integral weights, to make it work.

In role Enumeration§

See primary documentation in context for method pick

multi method pick(::?CLASS:U:)
multi method pick(::?CLASS:U: \n)
multi method pick(::?CLASS:D: *@pos)

It works on the defined class, selecting one element and eliminating it.

say Norse-gods.pick() for ^3;  # OUTPUT: «Þor␤Freija␤Oðin␤» 

In Range§

See primary documentation in context for method pick

multi method pick(Range:D:         --> Any:D)
multi method pick(Range:D: $number --> Seq:D)

Performs the same function as Range.list.pick, but attempts to optimize by not actually generating the list if it is not necessary.

In Any§

See primary documentation in context for method pick

multi method pick(--> Any)
multi method pick($n --> Seq)

Coerces the invocant to a List by applying its .list method and uses List.pick on it.

my Range $rg = 'α'..'ω';
say $rg.pick(3); # OUTPUT: «(β α σ)␤»