Matt Farina has a new post today looking at an "underutilized gem" he's found in the offerings of the Standard PHP Library (SPL) - the SplFixedArray.

Arrays in PHP are not arrays per the typical array data type. Instead, as Matt Butcher recently pointed out arrays in PHP are similar to hashes in other languages. This can be a very important point to know when tracking down bugs in code and to programmers coming to PHP from other languages. But, what if we wanted something like a traditional array data type? Maybe something that preserved numeric order. Enter SplFixedArray.

He gives an example of using the SplFixedArray object versus the normal array variables in a simple PHP snippet showing the preservation of numbering order. He also touches on the memory consumption difference between the two, with the fixed array coming in quite a bit lower than the normal array data type (around 25% based on his basic testing). There are some catches to using it, though including incompatibility with array methods and the fact that it doesn't implement things like Iterator or Countable interfaces.