How to binary search the ordered list in Perl

Want to binary search an ordered list. Can it be coded in Perl or someone points to a link to me?
For example,
list: (2, 100, 1000, 4001, 10001, ...)
Want to find the closest number from left in the list to 7000, which is 4001.
jl66Asked:
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vikaskhoriaCommented:
Check the below code for Binary search.
This may be of use to you.

Source:
http://www.perlmonks.org/?node_id=503154
Check the link for more details.
sub BinSearch
{
my ($target, $cmp) = @_;
my @array = @{$_[2]};
 
my $posmin = 0;
my $posmax = $#array;
 
return -0.5 if &$cmp (0, \@array, $target) > 0;
return $#array + 0.5 if &$cmp ($#array, \@array, $target) < 0;
 
while (1)
  {
  my $mid = int (($posmin + $posmax) / 2);
  my $result = &$cmp ($mid, \@array, $target);
  
  if ($result < 0)
    {
    $posmin = $posmax, next if $mid == $posmin && $posmax != $posmin;
    return $mid + 0.5 if $mid == $posmin;
    $posmin = $mid;
    }
  elsif ($result > 0)
    {
    $posmax = $posmin, next if $mid == $posmax && $posmax != $posmin;
    return $mid - 0.5 if $mid == $posmax;
    $posmax = $mid;
    }
  else
    {
    return $mid;
    }
  }
}

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