Need an array-like structure in PHP with minimal memory usage

Question

In my PHP script I need to create an array of >600k integers. Unfortunately my webservers memory_limit is set to 32M so when initializing the array the script a

Answer 1

A PHP Judy Array will use significantly less memory than a standard PHP array, and an SplFixedArray.

I quote "An array with 1 million entries using regular PHP array data structure takes 200MB. SplFixedArray uses around 90 megabytes. Judy uses 8 megs. Tradeoff is in performance, Judy takes about double the time of regular php array implementation."