Looping over keys of a hash

Note! This site is about Perl 6.
If you are looking for a solution for Perl 5, please check out the Perl 5 tutorial.

The same way we can loop over keys of a hash - after fetching them using the "keys" function.

The declaration of hashes in Perl 6 is similar to that in Perl 5 but when access individual elements in the hash it now keeps the % prefix. Thus the value of the key "Foo" will be %phone{"Foo"}. Similarly if $name contains "Foo" we can use the %phone{$name} expression to get back the relevant value.

As mentioned earlier the string interpolation of hashes requires curly braces around the statement.

tutorial/hash/loop_over_hash.p6

#!/usr/bin/env perl6
use v6;

my %phone = 
    "Foo" => 123,
    "Bar" => 456,
;

for keys %phone -> $name {
    say "$name %phone{$name}";
}

Output

tutorial/hash/loop_over_hash.p6.out

Bar 456
Foo 123

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