hi, I got this program from one of forums: http://www.perlguru.com/gforum.cgi?post=32920 its something like this: 
open(IN, "/path/outModified.pl") or die "$!";

while (my $line = <IN>) {
chomp($line);
my @array = (split (/\s+/, $line))[6, 7, 8];
# print "@array\n";
push @points, [ @array ];
}

close(IN);

print '@points : ', Dumper \@points;

open my $out_file, '>', "/path/dist_modified.pl" or die "cannot open: 
+$!\n";

for my $i1 ( 0 .. $#points -1 ){
my ( $x1, $y1, $z1 ) = @{ $points[$i1] };
for my $i2 ( 1 .. $#points){
my ( $x2, $y2, $z2 ) = @{ $points[$i2] };
my [COLOR="Red"]$dist [/COLOR]= sqrt(($x2 - $x1)**2 + ($y2 - $y1)**2 +
+ ($z2 - $z1)**2);
print $out_file "153L.pdb: the distance between CA $i1 and CA $i2 = $d
+ist\n";
}
}
close $out_file or die "cannot close file: $!\n";

[download]
I have to modify the above code to fit my program. my doubt is, if i have to compare the $dist with another value in another file which has the data: 
    col1  col2
    1     2.69
    2     2.97032
    3     3.25064
    4     3.53096
    5     3.81128
    6     4.0916
    7     4.37192
    8     ....... so on.....
    .
    .
    170   50.98
    171   51.086....so on

[download]

can I match the value of $dist with the column 2(col2) with its approximate value and retrieve the corresponding column1(col1)value? I have to match the value of $dist to the second column value(maximum is upto 50. any value of $dist greater than 50 should stop at the value(170 50.98)and retireve the value 170 for $dist compared with 50.98 or to its nearest high value. I dont know how to write this in perl. Can you help...

To make it clear, if the value of $dist = 2.84, then the program should search for second row in the file 2 2.97032 and print only 2. that is the first column.it this possible. I think i have to use regular expressions?? or pattern matching??

pls help I am a beginner in perl. Thank you in advance

In reply to retrive data from another file by comparing the values by amshi

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