Make a hash out of the file that you can use as a lookup table. Then loop through the array and print out the value if you have it, or the default value if you dont.

#!/usr/bin/perl -wT
use strict;

my @names = map {"name".$_} (1..5); # sneaky way to generate your exam
+ple array

my %name2number;  
while(<DATA>) {                     # generate the hash from the file
  my ($key,$value) = (split);
  $name2number{$key} = $value;
}

for my $name (@names) {             # loop through the array using the
+ lookup hash, 
                                    # or a default value
  my $number = $name2number{$name} || 999;
  print "$name => $number\n";
}

__DATA__
name1   4.5
name3   3.4
name5   6.5
name4   -7.9
name6   3.2

=OUTPUT
name1 => 4.5
name2 => 999
name3 => 3.4
name4 => -7.9
name5 => 6.5
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-Blake