Is there a way to subscript a Perl function which returns an array without using an intermediate var-CodePudding

When a Perl function returns an array is it possible to subscript the returned array?

my @tkeys = keys(%$someHashRef);
my $a0 = $tkeys[0];
# following not allowed by Perl
my $b0 = keys(%$someHashRef)[0];

Is there any way to extract an array element as a scalar from a function returning an array without using an intermediate array variable?

CodePudding user response：

You cannot subscript the subroutine/function call, but you can add parens and subscript those:

my ($value) = ( function() )[0];

Or using your example:

my $b0 = ( keys(%$someHashRef) )[0];

CodePudding user response：

You can use a list slice (( LIST )[ INDEXES ]).

my $b0 = ( keys( %$someHashRef ) )[ 0 ];

Better yet, a list assignment would do the trick.

my ( $b0 ) = keys( %$someHashRef );

In this particular case, you can also use

my $b0 = each( %$someHashRef );
keys( %$someHashRef );   # Reset iterator.

This latter approach avoids creating a scalar for each key of the stash.