adding numbers from different columns in one file

[Apfik]

Hi All,
I have a file with hundreds of lines and many columns and I need to process the numbers on each line in special way, basically adding and multiplying. My problem is that I don't know how to do it because the numbers are delimited in special way and I don't know how to read the correct numbers and then process them. Furthermore the numbers are in scientific form "1.112224e+00".

Each line is structured as following.

tab number space number space number tab tab number ..... number enter

here is also simple short example of one line


1.112224e+00 1.127221e+00 1.136870e+00 2.693811e+01 2.721771e+01 2.784709e+01 1.112224e+00 1.127221e+00 1.136870e+00 2.693811e+01 2.721771e+01 2.784709e+01 3.693811e+01 2.721771e+01 2.784709e+01

What I have to do is to add together number on position 1+4+7.... number, 2+5+8 ...number, 3+6+9 ....number, etc . The results should be three columns. Then I have to multiply each number from those three by coefficient and then add those three numbers together.

I forgot to mention that I want to do it in bash script.

Thank you very much for you advices and comments.

[Schmidt]

It's quite simple to do with perl and regular expressions. Here is a script that reads your file and extracts numbers:

#!/usr/bin/perl

use strict;

# Suppose that yo pass an input file name as script parameter :
my $file = $ARGV[0];

# open file for reading or die, printing an error :
open my $in, '<', $file or die "Cannot open $file: ".$!;

# an array where script will store numbers
my @strnumbers;
# Operator <> reads lines from an open filehandle
# and stores next line in $_ variable :
while(<$in>) {
# \s+ in regexp means any space character 
# (e.g. space, tab, newline, carriage return), repeated one or more times
  my @tmplist = split /\s+/, $_;
  push @strnumbers, @tmplist;
}

# now @strnumbers contains all extracted numbers as is (e.g. "1.112224e+00")

[Cabhan]

This sounds a lot like a homework problem, which are not allowed on our forums:
http://www.linuxforums.org/forum/lin...ums-rules.html

This is going to be a fairly difficult problem to solve using only Bash. It essentially breaks down to two problems:

1) How to extract the numbers
2) How to convert them from scientific notation

As Schmidt suggests, regular expressions are probably a good way to solve problem 1, and this can be done in just about any modern language, including Perl, Ruby, Python, Java, etc.

Problem 2 is more difficult, but I suspect that at least one of the libraries above can handle scientific notation, or has a library available to do it.

I'm going to close this thread because it sounds like a homework problem, but if you have any specific question on a specific concept, or if you have already written some code that you'd like advice on, feel free to start a new thread.