C-shell: How to create multiple arrays from a single line of standard input?

Question

I need to find a way to complete the following task using C-shell (I can't use a different shell):

There is a program that outputs polynomial factors from a larger polynomial, using Galois Field calculations. The output is a single line, and looks something like this (don't pay attention to the actual value of the numbers; I randomly chose them and they don't mathematically work out):

(0 1 4 6 7 8 11 12 13) = (0 1)^3 * (0 4 5) * (0 2 4 6)^4 * (0 2 3)^2

The way polynomial math works, if a factor is raised to an even number, then that factor is superfluous to the value of the polynomial. Sort of like multiplying by 1. What I need to do is extract the polynomial factors and eliminate the superfluous factors.

Using sed, I have been able to alter the above expression into the form of

(0 1) ^ 3 * (0 4 5) * (0 2 4 6) ^ 4 * (0 2 3) ^ 2

but I am unsure of how to proceed.

I want to take the above, input it into a C-shell script, and make the following array assignments:

Array A = (0 1)
Array B = (0 4 5)

I think the best route would be to first separate the polynomial factors into separate lines, like this:

(0 1) ^ 3
(0 4 5)
(0 2 4 6) ^ 4 
(0 2 3) ^ 2

but I am uncertain as to how to do this.

Can anyone provide any useful help or hints? Be aware that the number of polynomial factors will change, but I don't expect to ever have any more than 8. The exponent values aren't significant; I only need to determine whether they are even or odd. I can easily do that if they are assigned to a variable or an array. A maximum possible size of a single factor is probably around 50 individuals numbers inside the parentheses.

Answer 1

You probably want something like next:

#!/bin/tcsh

set str="(0 1) ^ 3 * (0 4 5) * (0 2 4 6) ^ 4 * (0 2 3) ^ 2"

echo "My string: ===$str==="
set arrnum = 0
foreach line ( "`echo '$str' | grep -oP '\([^)]*\)'`" )
    @ arrnum++
    set eval_line = "set array$arrnum = $line"
    eval "$eval_line"
end

echo "created $arrnum arrays (array1 .. array$arrnum)"
foreach i (`seq $arrnum`)
    set arrname = "array$i"
    echo "The content of $arrname"
    set temp = `eval echo '$'$arrname`
    foreach item ( $temp )
        echo $item
    end
end

It creates array1 .. arrayN for each (x x x x x) group. For your string:

(0 1) ^ 3 * (0 4 5) * (0 2 4 6) ^ 4 * (0 2 3) ^ 2

prints

My string: ===(0 1) ^ 3 * (0 4 5) * (0 2 4 6) ^ 4 * (0 2 3) ^ 2===
created 4 arrays (array1 .. array4)
The content of array1
0
1
The content of array2
0
4
5
The content of array3
0
2
4
6
The content of array4
0
2
3

Answer 2

Assuming you have the polynomial in a file named abc, you could use the following command to get the output you are looking for.

cat abc | tr '\052' '\n'

If you have the same in a variable say res, then you could use following command:

echo $res | tr '\052' '\n'