What are common causes of the "Out of memory" error in PHP applications?

The "Out of memory" error in PHP applications commonly occurs when the script exhausts the memory limit set in the php.ini configuration file. To solve this issue, you can increase the memory_limit value in the php.ini file or within your PHP script using the ini_set() function.

// Increase memory limit in PHP script
ini_set('memory_limit', '256M');