G'day rsFalse,

"What is your opinion?"

Unfortunately, you've provided very little information upon which an opinion might be based. Answers to the following would have been useful in your OP.

• How did you declare %hash? my? our? no strict 'vars'; and just let it pop into existence? something else?
• In what context are you using %hash?
• Why are you attempting to get rid of its contents (with undef or =())?
• Where's your benchmark code?
• Where's your benchmark results? [Sorry, but just saying "%hash = () is slower than undef %hash about 1.2 times" is not sufficient.]

Given all those unknowns, my opinion is that you should consider code like this:

{
    my %hash = (...);
    # operations on %hash here
}
# %hash doesn't exist here. Does that solve your problem?
[download]

Of course, with some answers to those questions, a better response might be forthcoming.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.