Hi,

I have a data file in which I need to delete a single entry value. The value will change, but its location in the file will always be the same.

Here is the section of the data file:

4.62399E+09 2.90871E+09 7.17338E+14
sb1 1.0 142r

I want to delete the 7.17338E+14 (or whatever is at that location. In my code I first open this file and find the previous line above sb1 ($oldine and $newline stuff) 

#!usr/bin/perl
use warnings;
use strict;
#
my ($line)= "4.62399E+09  2.90871E+09  7.17338E+14";
my ($oldline) = "4.62399E+09  2.90871E+09  7.17338E+14";
my ($newline) = "4.62399E+09  2.90871E+09  ";
#
    open (IN, "sdef");
      while (<IN>) {
          if ($_ =~ /sb1       1.0  142r/ ) {
             $oldline = substr($line, 10, 38);
             $newline = substr($oldline, 0, 26);  
           } else {
             $line = $_;
           }
      }
    close(IN);
#
    chomp($oldline);
    chomp($newline);
    print "new = $newline\n";
    print "old = $oldline\n";
#
    open (IN, "sdef");
      open (OUT, ">sdef_steel")  or die "Cannot open file for writing:
+ $+!" ;
       while (<IN>) {
           s/si1 L      1000   1000   /si1 L      1000   /; # works ok
           s/2150   2151   1035/2150   2151       /;       # works ok
           s/$oldline/$newline/;                        # doesn't work
           s/sp1 D     (\d+.\d+E[-+]\d+)  /sp1 D     /;    # works ok
           print OUT $_;
       }
       close (IN);
       close (OUT);

[download]

Upon running, I get:

perl test.pl
new = 4.62399E+09 2.90871E+09
old = 4.62399E+09 2.90871E+09 7.17338E+14

Okay, so far so good. But if I grep the new file sdef_steel for 7.17338E+14, it still exists in the sdef_steel file.
It is not recognizing my $oldline string. I think the problem is how I am declaring it.
I have tried both my($oldline) = "txtxxt"; and my($oldline) = "1.234". Of course, the exponential is a combo.
I had thought declaring it as text (string) would be the best method.
So, what is the best way to handle subsitution of exponentials in a single data line?

In reply to how to read in a line containing exponentials by pattobw

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