You seem to be mixing up terms.
Hash keys are used as an index in the hash. Hash keys are always strings, and are always defined. There's no such thing as an undefined hash key.
Having said that:
if (exists $hash{key}) { ... } # True if there's a value for 'ke
+y'
if (defined $hash{key}) { ... } # True if there's a value for 'ke
+y' and the value is defined.
if ($hash{key}) { ... } # True if there's a value for 'ke
+y' and the value is true.
defined is the test to use to test whether something is defined. To test the existance of a hash key, use exists.
-
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.
|