PHP object and reference values

Variable assignment versus object assignmentCopy the code

       
    // Declare a variable and assign a value
    $a = 1; 
    // Assign the value of the data type to a variable
    $b = $a; 

    // Change the value of $a
    $a = 2; 

    $a and $b are two independent memory space changes, one of which is unaffected by the other
    echo $b; / / 1

    class Person{
        public $name;
        public $age;

    }

    // Assign data of the object type to a variable
    $p = new Person;

    // By modifying the value of the attribute, we can determine the way the object is passed in object-oriented
    $p->name = 'jesse';

    // If the value is successfully modified, the value is passed by reference
    echo $p->name; // jesse

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Copy the code

Case Explanation:

In this case, the method of assigning a variable is compared with the method of assigning an object
$b =$a; The assignment mode of is “copy assignment”, so when modifying its source value (
$The value of a),$The value of B is not affected.
$A and$The memory diagram of B is as follows:The code
$p->name = ‘jesse’; Assigns the data type to$$p = $p = $p = $p = $p = $p = $p

       
    class Person
    {
        public $name;
        public $age;

        // Assign data of the object type to a variable
        $p = new Person;

        // By modifying the value of the attribute, we can determine the way the object is passed in object-oriented
        $p->name = 'jesse';

        // Assign the object to another variable
        $m = $p;

        // Another variable modifies the attribute value
        $m->name = 'Marry';

        // Output the result of the source variable assignment variable accessing the internal attribute
        echo $p->name, $m->name;
    }

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$m =$p; $m is a copy of the object. $m is a copy of the object. Or do you pass by reference? The code memory relationship is as follows:Therefore, the last two objects’ property values are changed to Marry!!

So what happens when you pass by reference?

       
    class Person
    {
        public $name; 
        public $age; 
    } 

    // Assign data of the object type to a variable
    $p = new Person; 

    // By modifying the value of the attribute, we can determine the way the object is passed in object-oriented
    $p->name = 'jesse';

    // Assign the object to another variable
    $m = &$p;

    // Another variable modifies the attribute value
    $m->name = 'Marry';

    // Output the result of the source variable assignment variable accessing the internal attribute
    echo $p->name, $m->name;

? >
Copy the code

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