Why do you need $ when accessing array and hash elements in Perl?

Question

Since arrays and hashes can only contain scalars in Perl, why do you have to use the $ to tell the interpreter that the value is a scalar when accessing array or hash elemen

Answer 1

In Perl 5 (to be changed in Perl 6) a sigil indicates the context of your expression.

• You want a particular scalar out of a hash so it's $hash{key}.
• You want the value of a particular slot out of an array, so it's $array[0].

However, as pointed out by zigdon, slices are legal. They interpret the those expressions in a list context.

• You want a lists of 1 value in a hash @hash{key} works

• But also larger lists work as well, like @hash{qw}.

• You want a couple of slots out of an array @array[0,3,5..7,$n..$n+5] works

• @array[0] is a list of size 1.

There is no "hash context", so neither %hash{@keys} nor %hash{key} has meaning.

So you have "@" + "array[0]" <=> < sigil = context > + < indexing expression > as the complete expression.