So are there any more efficient way to do that ?

A better question might be is using eval the most inefficient , least secure and most incomprehensible method? To which the answer is yes.

Now seriously string eval and user input or even file input is a recipe for disaster. As you currently don't seem to understand why or how all I can do is suggest you avoid eval "this" until you understand how dangerous it really is.

If you were to outline what you are actually trying to do (as opposed to how do I take this loaded gun, put it to my head and wait for someone to pull the trigger ;-) I am sure you will find lot's of efficient, secure and fast suggestions.

From the information you give the if/elsif/elsif/else structure you show IS the most efficient structure in terms of speed and security. There are many other ways to do it, typically a dispatch hash, but these are all slower. Just about anything will be more secure than a string eval where you let user input in. 

my %dispatch = (
  '>' => sub { $_[0] > $_[1] },
  '<' => sub { $_[0] < $_[1] },
  '=='=> sub { $_[0] == $_[1] },
);



# now in loop
    if ( $dispatch{$sop} ) {
        # OK so $sop exists, get the right function from
        # the dispatch hash and call it with the args we want 
        if ( &{$dispatch{$sop}}( $tmpdata[8], $sport ) ) {
             # yabada
        }
        else {
             # ! yabada
        }
    }
    else {
        die "Illegal op $sop. Are you trying to hack me?\n";
    }
# end loop

[download]

cheers

tachyon

In reply to Re: How to do that with eval ? by tachyon
in thread How to do that with eval ? by iwanthome

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