Sponsored Content
Top Forums Shell Programming and Scripting Replacement for eval in Perl?????? Post 302211275 by cbkihong on Thursday 3rd of July 2008 03:47:49 AM
Old 07-03-2008
Why not? In that case you do not even need to use variable variables at all, if all of the data are from a file. Of course, how to do it depends on how you read from the file.
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

perl: eval and constants

is it possible to use eval to create constants in perl? i cannot seem to get anything to work, and my searches are turning up little to nothing. an example of what i am trying to do is this: 2 arrays: array 1: 'FOOD','NUMBER','OS' array 2: 'pizza','two','unix' loop through the arrays and... (5 Replies)
Discussion started by: effigy
5 Replies

2. Shell Programming and Scripting

Replacement of sed with perl

Hi using the below cmd i am identifying wheether last character in each line in thousands of files as semicolon or not.If last character is semicolon i am removing semicolon .If last character is not semicolon then i am appending next line to present line . For example my input file consists of... (4 Replies)
Discussion started by: dbsurf
4 Replies

3. Shell Programming and Scripting

redefine warning(Eval) in perl

Here is my perl Program: #!/usr/bin/perl -w my $a="sam"; my $b="ste"; my $c="abcdef"; my $d=931; $str=" @<<<<< @>>>>>>>>>> @|||||||||||||||||||| @######### \$a,\$b,\$c,\$d ."; open(FILE,">abc.txt"); $temp="format FILE = $str"; eval $temp; write FILE; print FILE "\n\n"; (3 Replies)
Discussion started by: sameerstephen
3 Replies

4. Shell Programming and Scripting

Replacement of sentence in perl

Hi, I have 3 arrays: @arr1=("Furthermore, apigenin treatment increased the level of association of the RNA binding protein HuR with endogenous p53 mRNA","one of the mechanisms by which apigenin induces p53 protein expression is enhancement of translation through the RNA binding protein... (1 Reply)
Discussion started by: vanitham
1 Replies

5. Shell Programming and Scripting

Strange result of eval, how does eval really work with ssh?

Hi all, some small script with eval turned me to crazy. my OS is linux Linux s10-1310 2.6.16.53-0.8.PTF.434477.3.TDC.0-smp #1 SMP Fri Aug 31 06:07:27 PDT 2007 x86_64 x86_64 x86_64 GNU/Linux below script works well #!/bin/bash eval ssh remotehost date eval ssh remotehost ls below... (1 Reply)
Discussion started by: summer_cherry
1 Replies

6. Shell Programming and Scripting

Help with perl eval command .....

Hi All, I read the above written code (perl code) in another perl script and evaluates this code for each line of text file,but using exit statement in code make this not to work and i could not get the desired results. However if i use return it works fine. I just need to know why it doesn't... (1 Reply)
Discussion started by: sarbjit
1 Replies

7. Shell Programming and Scripting

Perl eval problem

Hello All, I am trying to use perl eval in a complex code and below given is a pseudo code of my logic. Here $result evalutes to empty. Please help.How should I retrieve of $t where $f just hold the name of varaible i.e t $t=10; $f='$t'; $result=eval "\$$f"; print "$result\n"; (3 Replies)
Discussion started by: prasperl
3 Replies

8. Shell Programming and Scripting

Error in eval eval command to print html tags

anyone has any info on why this is complaining??? vivek@vivek-c5e55ef2e ~/TAC $ zoneCounter=1 vivek@vivek-c5e55ef2e ~/TAC $ optUsage1=23% vivek@vivek-c5e55ef2e ~/TAC $ eval eval echo "<th>Zone $zoneCounter </th><th align=\"left\"> \$optUsage$zoneCounter </th>" -bash: syntax error... (1 Reply)
Discussion started by: vivek d r
1 Replies

9. Shell Programming and Scripting

Error in eval eval command to print html tags

anyone has any info on why this is complaining??? vivek@vivek-c5e55ef2e ~/TAC $ zoneCounter=1 vivek@vivek-c5e55ef2e ~/TAC $ optUsage1=23% vivek@vivek-c5e55ef2e ~/TAC $ eval eval echo "<th>Zone $zoneCounter </th><th align=\"left\"> \$optUsage$zoneCounter </th>" -bash: syntax error... (13 Replies)
Discussion started by: vivek d r
13 Replies

10. Shell Programming and Scripting

Word replacement in Perl

I have the following string : Cat dog fox catepillar bear foxy I need to replace "cat" and "fox" words from this sentence to word "animal" I do the following: $Str1="cat"; $Str2="fox"; $NewStr="animal"; open(F1, "<$inputFile") or die "Error: $!"; open(F2, ">$outputFile") or... (1 Reply)
Discussion started by: AIX_30
1 Replies
Math::Symbolic::Variable(3pm)				User Contributed Perl Documentation			     Math::Symbolic::Variable(3pm)

NAME
Math::Symbolic::Variable - Variable in symbolic calculations SYNOPSIS
use Math::Symbolic::Variable; my $var1 = Math::Symbolic::Variable->new('name'); $var1->value(5); my $var2 = Math::Symbolic::Variable->new('x', 2); my $var3 = Math::Symbolic::Variable->new( { name => 'variable', value => 1, } ); DESCRIPTION
This class implements variables for Math::Symbolic trees. The objects are overloaded in stringification context to return their names. EXPORT None by default. METHODS
Constructor new First argument is expected to be a hash reference of key-value pairs which will be used as object attributes. In particular, a variable is required to have a 'name'. Optional arguments include a 'value', and a 'signature'. The value expected for the signature key is a reference to an array of identifiers. Special case: First argument is not a hash reference. In this case, first argument is treated as variable name, second as value. This special case disallows cloning of objects (when used as object method). Returns a Math::Symbolic::Variable. Method value value() evaluates the Math::Symbolic tree to its numeric representation. value() without arguments requires that every variable in the tree contains a defined value attribute. Please note that this refers to every variable object, not just every named variable. value() with one argument sets the object's value if you're dealing with Variables or Constants. In case of operators, a call with one argument will assume that the argument is a hash reference. (see next paragraph) value() with named arguments (key/value pairs) associates variables in the tree with the value-arguments if the corresponging key matches the variable name. (Can one say this any more complicated?) Since version 0.132, an equivalent and valid syntax is to pass a single hash reference instead of a list. Example: $tree->value(x => 1, y => 2, z => 3, t => 0) assigns the value 1 to any occurrances of variables of the name "x", aso. If a variable in the tree has no value set (and no argument of value sets it temporarily), the call to value() returns undef. Method name Optional argument: sets the object's name. Returns the object's name. Method signature signature() returns a tree's signature. In the context of Math::Symbolic, signatures are the list of variables any given tree depends on. That means the tree "v*t+x" depends on the variables v, t, and x. Thus, applying signature() on the tree that would be parsed from above example yields the sorted list ('t', 'v', 'x'). Constants do not depend on any variables and therefore return the empty list. Obviously, operators' dependencies vary. Math::Symbolic::Variable objects, however, may have a slightly more involved signature. By convention, Math::Symbolic variables depend on themselves. That means their signature contains their own name. But they can also depend on various other variables because variables themselves can be viewed as placeholders for more compicated terms. For example in mechanics, the acceleration of a particle depends on its mass and the sum of all forces acting on it. So the variable 'acceleration' would have the signature ('acceleration', 'force1', 'force2',..., 'mass', 'time'). If you're just looking for a list of the names of all variables in the tree, you should use the explicit_signature() method instead. Method explicit_signature explicit_signature() returns a lexicographically sorted list of variable names in the tree. See also: signature(). Method set_signature set_signature expects any number of variable identifiers as arguments. It sets a variable's signature to this list of identifiers. Method to_string Returns a string representation of the variable. Method term_type Returns the type of the term. (T_VARIABLE) AUTHOR
Please send feedback, bug reports, and support requests to the Math::Symbolic support mailing list: math-symbolic-support at lists dot sourceforge dot net. Please consider letting us know how you use Math::Symbolic. Thank you. If you're interested in helping with the development or extending the module's functionality, please contact the developers' mailing list: math-symbolic-develop at lists dot sourceforge dot net. List of contributors: Steffen Mueller, symbolic-module at steffen-mueller dot net Stray Toaster, mwk at users dot sourceforge dot net Oliver Ebenhoeh SEE ALSO
New versions of this module can be found on http://steffen-mueller.net or CPAN. The module development takes place on Sourceforge at http://sourceforge.net/projects/math-symbolic/ Math::Symbolic perl v5.10.1 2011-01-01 Math::Symbolic::Variable(3pm)
All times are GMT -4. The time now is 02:19 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy