comment on

You're being bitten by precedence. Ternary ?: has a higher precedence than =, so what perl parses is:

Y:\tmp>perl -MO=Deparse,-p 470538.pl
(my(%hash) = ('A', 'on', 'B', 'on', 'C', 'off', 'D', 'off', 'E', 'off'
+));
foreach $_ (keys(%hash)) {
    my($result);
    (((exists($hash{$_}) && ($hash{$_} eq 'on')) ? ($result = 'OK') : 
+$result) = 'KO');
    print($result, "\n");
}
470538.pl syntax OK
[download]

You're effectively doing ($result='OK')='KO' in the case of a match, hence your output. The solution is of course to use parentheses:

   (exists $hash{$_} and $hash{$_} eq 'on') 
      ? ($result = 'OK') 
      : ($result = 'KO');
[download]

Nice gotcha you found there :)

CU
Robartes-

In reply to Re: Question about ternary condition by robartes
in thread Question about ternary condition by Tomtom

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


Pathologically Eclectic Rubbish Lister
	PerlMonks