In this case, the example is simply trying to show that results can be cached. As you say, we could reduce storage cost a lot and speed a little by using an array, string, or vector. Though one has to be careful with that as a single input of (for example) 1e18 will work fine with the hash but blow up with the other methods.
It turns out using a module (e.g. ntheory) for is_prime() is easier and faster overall anyway. No need to spend time on sieving, caching, memoize, etc. for these small sizes. But looking at the full context for this code, this is completely backwards -- he's using primality as a simple test vehicle to show caching.
-
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.
|