On 3/13/12 Tue Mar 13, 2012 9:11 AM, "oxy" <oxyo...@googlemail.com>
scribbled:
> hi all,
>
> I have a problem with the following structure:
>
> while(<file>){$thevariable=$1 if (/variable1=(.*)/)};
>
> Now I wanna be sure that variable1 was really set in the above
> statement (it could have an old value from a previous embracing loop).
You could reset $thevariable before entering the loop:
undef $thevariable;
> Then I tried:
>
> while(<file>){if (/variable1=(.*)/)
> {$thevariable=$1} else {$thevariable="nonset"};
>
> The problem is, the second while statement is resetting $thevariable
> for every line in the file and not only for the matching one. The
> else {$thevariable="notset"} option should be actually only run if
> we reach the end without matching. But both while structures above
> aren't solving my problem.
Put a print statement in the true branch of the if statement so you can tell
if and when the match succeeds and $thevariable is set. The variable will be
reset if there are any non-matching lines following a line that matches, so
you will need to avoid doing that.
You can reset the variable to undef before the loop, set it only if a line
matches, and check for definedness after the loop to see if it was set:
if( defined $thevariable ) {
print "Variable was set to $thevariable\n";
}else{
print "No match\n";
}
For more help, you should post a short, complete program, including some
typical data lines, that demonstrates the problem you are having.
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