Using a hash for uniqueness is the canonical means of maintaining a unique set with Perl. However, the 'values' needn't be "arbitrary". There are all sorts of uses for the values, such as:
- A count of how many times a particular entry has been seen.
- An anonymous arrayref (or in other words, a HoA - hash of arrays), where the array pertaining to each hash entry contains a list of positions at which a particular entry was found.
- A priority for a given entry (priority, sort order, timestamp, or whatever other info might be interesting).
Your second option, "Use an array; filtering it through a routine that makes it unique" is probably going to still employ a hash as the means of filtering. The array simply would keep the entries in some specific order. But as mentioned above, you can keep track of order by simply using the filter hash's values.
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
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! —
Posts may use any of the Perl Monks Approved HTML tags:
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, 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, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.
| & || & |
| < || < |
| > || > |
| [ || [ |
| ] || ] ||