There are three main ways to convert objects into arrays in PHP. 1. Use (array) casting is suitable for simple objects, but private attributes will be prefixed with class name, affecting the key name; 2. Use json_encode and json_decode to combine nested structures and ignore access modifiers, but resources and closures will be discarded; 3. Write recursive functions to finely control the conversion process, which is suitable for complex object structures, and can expand processing logic; in addition, attention should be paid to the impact of access control on key names, the inability to convert resources and closures, the need for additional processing of special objects, and performance issues. Just select the appropriate method according to the object structure and needs.

In PHP, converting objects into arrays is a common requirement, especially when handling JSON data, database results, or API responses. While PHP provides some simple ways to convert, sometimes the default behavior may not be as expected, especially if the object contains nested objects or private properties.

1. Basic conversion: Use type conversion (array)

The easiest way is to use (array) cast:

 $myArray = (array) $myObject;

This method is suitable for simple objects, but the following points need to be paid attention to:

• Public properties retain the original name;
• Protected properties will be preceded by * and spaces;
• Private attributes will prepend class names and spaces;

This will cause the keys of the array to become complicated and are not conducive to subsequent processing.

2. Use json_decode and json_encode combination

This is a "short" method commonly used by many people, especially suitable for nested objects:

 $myArray = json_decode(json_encode($myObject), true);

The principle of this method is:

• First use json_encode to convert the object into a JSON string;
• Then use json_decode to convert the string into an array, and set the second parameter to true to return the associative array;

The advantage is that it is OK to handle nested structures and ignore the effects of access modifiers. The disadvantage is that if there is a resource type (such as a database connection) or a closure function in the object, it will be discarded.

3. Custom recursive functions to handle complex objects

If you need more granular control, such as handling private properties, nested objects, or want to preserve certain structures, you can write a recursive function:

 function objectToArray($object) {
    if (is_object($object)) {
        $object = get_object_vars($object);
    }

    return array_map(function($value) {
        return is_object($value) || is_array($value) ? objectToArray($value) : $value;
    }, $object);
}

The idea of this function is:

• If it is an object, first use get_object_vars to get all attributes;
• Then process each value recursively;
• No matter how deep the nesting is, it will eventually be converted into an array;

This method is suitable for complex structures and also allows you to extend logic as needed, such as filtering certain properties or performing type conversions.

4. Precautions and FAQs

• Access control affects key names : When using (array) conversion, the private attribute name will be prefixed with the class name;
• Resources and closures cannot be converted : resource types such as file handles, PDO objects, or anonymous functions cannot be converted correctly;
• Date objects or special classes need to be processed : For example, DateTime objects may become empty or have unclear structures after being converted into an array, and additional processing is required;
• Performance considerations : If the data volume is large, using json_encode/decode may affect performance. It is recommended to use recursive functions to optimize the processing at this time;

Basically that's it. Just choose the right method according to your object structure and needs, it is not complicated but it is easy to ignore details.

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