comment on

examples:

perl -wMstrict -e "my %hash = (foo => 'x',  bar => '',  baz => undef);
for (qw/foo bar baz quux/) {
    printf qq($_ exists:%s:  $_ defined:%s:  $_ true:%s: \n),
    exists($hash{$_}), defined($hash{$_}), $hash{$_} ? 1 : ''
    }"
foo exists:1:  foo defined:1:  foo true:1:
bar exists:1:  bar defined:1:  bar true::
baz exists:1:  baz defined::  baz true::
quux exists::  quux defined::  quux true::
[download]

In reply to Re^2: hash undef? by Anonymous Monk
in thread hash undef? by Anonymous Monk

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.


more useful options
	PerlMonks