More often than not, we need to store a complex array in a database or in a file from PHP. Some of us were probably looking for some kind of built-in function to accomplish this task. Complex arrays - they are arrays with elements of more than one data type or array. But we already have a convenient solution to deal with this situation.Serialize() function:
serialize() - it is a built-in PHP function that is used to serialize a given array. The serialize() function takes one parameter, which is the data we want to serialize, and returns a serialized string.
Unserialize() function:unserialize() - this is a built-in php function that is used to deserialize a given serialized array to revert to the original complex array value, $myvar.
Note:for more in-depth knowledge, you can check out PHP | Serializing data articles.