Editing Foreach loop (section)

=== Raku ===
In [[Raku (programming language)|Raku]], a sister language to Perl, ''for'' must be used to traverse elements of a list (''foreach'' is not allowed). The expression which denotes the collection to loop over is evaluated in list-context, but not flattened by default, and each item of the resulting list is, in turn, aliased to the loop variable(s).

List literal example:

<syntaxhighlight lang="Perl6">
for 1..4 {
    .say;
}
</syntaxhighlight>

Array examples:

<syntaxhighlight lang="Perl6">
for @arr {
    .say;
}
</syntaxhighlight>

The for loop in its statement modifier form:

<syntaxhighlight lang="Perl6">
.say for @arr;
</syntaxhighlight>

<syntaxhighlight lang="Perl6">
for @arr -> $x {
    say $x;
} 
</syntaxhighlight>

<syntaxhighlight lang="Perl6">
for @arr -> $x, $y {    # more than one item at a time
    say "$x, $y";
} 
</syntaxhighlight>

Hash example:

<syntaxhighlight lang="Perl6">
for keys %hash -> $key {
    say "$key: $hash{$key}";
}
</syntaxhighlight>

or

<syntaxhighlight lang="Perl6">
for %hash.kv -> $key, $value {
    say "$key: $value";
}
</syntaxhighlight>

or

<syntaxhighlight lang="Perl6">
for %hash -> $x {
    say "$x.key(): $x.value()";    # Parentheses needed to inline in double quoted string
}
</syntaxhighlight>


Direct modification of collection members with a doubly pointy block, ''<->'': 

<syntaxhighlight lang="Perl6">
my @arr = 1,2,3;
for @arr <-> $x {
    $x *= 2;
}
# Now @arr = 2,4,6;
</syntaxhighlight>