Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: AWK equation evaluation.
Top Forums Shell Programming and Scripting AWK equation evaluation. Post 302146814 by srdgeo on Thursday 22nd of November 2007 09:59:12 AM
Old 11-22-2007
AWK equation evaluation.
Hi,

Is there a way to evaluate an equation contained in a string within an AWK script?

For example:
A = "(5*2)-1" (this equation is read from a file and varies line by line)

In this example, I can't see any way to get an answer of 9 unless I do:

cmd = "awk 'BEGIN{print "A"}'"
cmd | getline A

The above method works fine but it's rather slow when dealing with large files!

Does anybody know of a better way of achieving the same result within the main AWK script?

Any help and advice appreciated.

Steve
 

8 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

equation calculation on Unix

Hay, guys, Any ideas how to calculate like this: in first file, there're number of lines listing 2+3, 6*9 ....... Then, how to get the result and put them in another file in format: 2+3 5 6*9 54 ...... sheerly by shell command, no scripts required. (4 Replies)
Discussion started by: robbinGlasses
4 Replies

2. Shell Programming and Scripting

Perl - maths equation - need help

if input to the perl program is ' ( p * ((a+b) * (c+d))) + q ' it shuld give the output as ' pac + pad + pbc + pbd + q ' .can anyone suggest a way to do this ? (7 Replies)
Discussion started by: Anuj8584
7 Replies

3. High Performance Computing

Performance Equation

I'm running a MPI program using a cluster of 4 machines(different machines of different processing power,cpu utilization etc.). I'm trying to balance the computation among the machine to get the minimum execution time for that. I tried to balance it by creating a threshold value by taking the load... (1 Reply)
Discussion started by: chamila1986
1 Replies

4. Shell Programming and Scripting

Using AWK in IF evaluation in KSH

Hi - I have an expression that evaluates to "Alive" or some other condition. e.g. if I run :- awk -F \| '{gsub(/]*/,"",$4); print $4 }' then the output is "Alive". I want to be able to test this as the result may be some other condition other than "Alive". I have tried the following... (4 Replies)
Discussion started by: sniper57
4 Replies

5. UNIX for Dummies Questions & Answers

cp command evaluation

Hi all! I'm writting one script to copy a file in various folders, but there are 2 things to validate. First that the folder where i'll be cpying exists, and second that i have permissions to copy the file in it. so far i have found the way to validate the folder exists, but when trying to... (6 Replies)
Discussion started by: feliperivera
6 Replies

6. Shell Programming and Scripting

Help with insert a value equation in bash script

HI All, I have a script in bash that i want that script will perform action When the size of a particular folder exceeds the 80%. Here is an example of script that result is exactly 80% : #!/bin/bash CHECK=$(df -h /var/log/syslog | grep '80%' | xargs echo | cut -d' ' -f5) if ];... (1 Reply)
Discussion started by: Aviel.shani
1 Replies

7. Homework & Coursework Questions

Solving heat equation using crank-nicolsan scheme in FORTRAN

! The one-dimensional PDE for heat diffusion equation ! u_t=(D(u)u_x)_x + s where u(x,t) is the temperature, ! D(u) is the diffusivity and s(x,t) is a source term. ! Taking D(u)= 1 and s(x,t)=0 gives ! u_t= u_xx ! uniform one dimensional region |x|<1 for t>0 ! uniform mesh size delta x=0.1 !... (1 Reply)
Discussion started by: watto1
1 Replies

8. Programming

E**(i*pi)=-1 or e**(j*pi)=-1, something I found out in Python using part of Eulers Identit equation.

Well guys and gals I have discovered after all these years that Python does complex numbers without the 'complex()' function or 'cmath' import. It is well known that Euler's Identity E**(i*pi)+1=0 so I decided to experiment Last login: Fri Dec 13 18:27:30 on ttys000 AMIGA:amiga~> python3.8... (0 Replies)
Discussion started by: wisecracker
0 Replies

LEARN ABOUT CENTOS

glgetclipplane

GLGETCLIPPLANE(3G)						   OpenGL Manual						GLGETCLIPPLANE(3G)

NAME

       glGetClipPlane - return the coefficients of the specified clipping plane

C SPECIFICATION

       void glGetClipPlane(GLenum plane, GLdouble * equation);

PARAMETERS

       plane
	   Specifies a clipping plane. The number of clipping planes depends on the implementation, but at least six clipping planes are
	   supported. They are identified by symbolic names of the form GL_CLIP_PLANEi where i ranges from 0 to the value of GL_MAX_CLIP_PLANES -
	   1.

       equation
	   Returns four double-precision values that are the coefficients of the plane equation of plane in eye coordinates. The initial value is
	   (0, 0, 0, 0).

DESCRIPTION

       glGetClipPlane returns in equation the four coefficients of the plane equation for plane.

NOTES

       It is always the case that GL_CLIP_PLANEi = GL_CLIP_PLANE0 + i.

       If an error is generated, no change is made to the contents of equation.

ERRORS

       GL_INVALID_ENUM is generated if plane is not an accepted value.

       GL_INVALID_OPERATION is generated if glGetClipPlane is executed between the execution of glBegin() and the corresponding execution of
       glEnd().

SEE ALSO

       glClipPlane()

COPYRIGHT

       Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see
       http://oss.sgi.com/projects/FreeB/.

AUTHORS

       opengl.org

opengl.org							    06/10/2014							GLGETCLIPPLANE(3G)
All times are GMT -4. The time now is 08:40 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy