How many ways are there to assign values to variables in php?
3 ways to assign values to variables in php
1. Value assignment, such as $a=1,$b=$a, etc.;
2. Reference assignment, for example $a=&$b, that is, $a and $b both point to the same storage variable value address in memory;
3. Reference counting value transfer, The default value-passing method for objects in php and js is reference counting. The example is as follows:
<?php class Dog{ public $name="小花"; public $leg=4; } $a=new Dog;//此时,$a指向了内存中的一个地址(假设0XFFAD[1]),该地址又指向最终对象的值 $b=$a;//此时,$b和$a都指向了内存中的另一个地址(0XFFAD[2]),该地址又指向最终对象的值 var_dump($b->leg);//结果是int 4 $b=999; var_dump($b);//结果是int 999; var_dump($a);//此时的结果不是int 999,而是object(Dog)[1] public 'name' => string '灏忚姳' (length=6) public 'leg' => int 4
It can be seen that the object's value-passing method is somewhat different from the second reference-counting method. difference.
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