use splice

my @array = (0..7);
splice @array, 4, 0, ('inserted-array');
print "@array\n";
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Note: the other array operators (push, pop, shift, and unshift) can all be done with splice as well:

# push @array, @others;
splice @array, @array, 0, @others;

# my $element = pop @array
my $element = splice @array, $#array, 1;

# my $element = shift @array
my $element = splice @array, 0, 1;

# unshift @array, @others
splice @array, 0, 0, @others;
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Update: Fixed slight bug in push and pop equivalents. Ty AnomalousMonk