Understanding this is part of understanding how references work.
You are not changing the actual values in either the function or the original data structure. Those values are a pointer saying, The real data is over there. Instead you're manipulating the value of what the reference is pointing to. Since both are pointing there, the side-effect is that both see the change.
To achieve the effect that you are looking for, you need to change the value of the hash by creating new references. Like this:
sub push_1 {
my %hash = @_;
for (keys %hash) {
$hash{$_} = [ @{ $hash{$_} }, 1 ];
}
}
UPDATE: It became clear in chatter that I should make it precise what references are involved. The references that I'm talking about are the anonymous array references that are the values of the hash.
-
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.
|