?
Solved

perl loop and variable

Posted on 2013-12-05
5
Medium Priority
?
280 Views
Last Modified: 2013-12-05
Hi,
Please see code below.
I'm trying to check the value of the $emp1, $emp2, etc... variables by using a for loop.
I thought the best way to do it (there are actually 15 different emp variables not just 4) would be to use a loop.
The error I'm getting is:
----------
Scalar found where operator expected at t.pl line 10, near "$emp$i"
(Missing operator before $i?)
-----------

I'm not understanding that error or why this isn't working. Any suggestions how I can modify the code below to make it work the way I would like?


$emp1=0;
$emp2=1;
$emp3=22;
$emp4=0;


for($i=1;$i<5;$i++){

#I thought $emp$i would resolve to  $emp1, $emp2, $emp3, etc....  but it's not.
        if($emp$i > 0){  # Error on this line
        print "emp holds a value greater then zero\n";
        }#end of if

  }#end of for
0
Comment
Question by:nachtmsk
  • 3
  • 2
5 Comments
 
LVL 85

Accepted Solution

by:
ozo earned 2000 total points
ID: 39698216
you can use ${"emp$i"}, though I do not recommend that technique
0
 
LVL 1

Author Comment

by:nachtmsk
ID: 39698236
Thanks ozo. Why don't your recommend it?
0
 
LVL 85

Expert Comment

by:ozo
ID: 39698244
See `perldoc perlref`
       This is powerful, and slightly dangerous, in that it's possible to
       intend (with the utmost sincerity) to use a hard reference, and
       accidentally use a symbolic reference instead.  To protect against
       that, you can say

           use strict 'refs';

       and then only hard references will be allowed for the rest of the
       enclosing block.  An inner block may countermand that with

           no strict 'refs';
0
 
LVL 85

Expert Comment

by:ozo
ID: 39698310
Why not use

@emp=(undef,0,1,22,0);

for( @emp[1..4] ){

#I thought $emp$i would resolve to  $emp1, $emp2, $emp3, etc....  but it's not.
        if( $_ > 0 ){  # Error on this line
        print "emp holds a value greater then zero\n";
        }#end of if
0
 
LVL 1

Author Comment

by:nachtmsk
ID: 39698331
That's a good idea. Thanks.
I went ahead and put in 15 if statements. All I needed to do was push some values into an array if the emp$x id had a value > 0.
 Not elegant, but it works fine. If I have time I'll go back and change it to above. In a bit of a time crunch.
0

Featured Post

[Webinar On Demand] Database Backup and Recovery

Does your company store data on premises, off site, in the cloud, or a combination of these? If you answered “yes”, you need a data backup recovery plan that fits each and every platform. Watch now as as Percona teaches us how to build agile data backup recovery plan.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Email validation in proper way is  very important validation required in any web pages. This code is self explainable except that Regular Expression which I used for pattern matching. I originally published as a thread on my website : http://www…
In the distant past (last year) I hacked together a little toy that would allow a couple of Manager types to query, preview, and extract data from a number of MongoDB instances, to their tool of choice: Excel (http://dilbert.com/strips/comic/2007-08…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…
Six Sigma Control Plans
Suggested Courses

621 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question