How to use basic assignment operators in PHP operators

In the previous article, we learned about type operators. If necessary, please read "How to use type operators in php operators". This time we introduce to you another operator, the basic assignment operator. You can refer to it if you need it.

There are many operators in php. Today we will learn a simple operator, the basic assignment operator.

The basic assignment operator is "=". Its precedence is lower than other operators, so this operator is often read last.

Let’s look at a small example.

<?php
$b=4;
$a = $b + 5; // $a 现在成了 9，而 $b 成了 4。
echo "a现在值为".$a;
echo "<br>";
echo "b现在值为".$b;
echo "<hr>";
$a = $b + $a;
echo "a现在值为".$a;
echo "<br>";
echo "b现在值为".$b;
?>

The result of this example is

We can see that in this example, the value of our "$a" becomes 9. The value of "$b" becomes 4; when the operation "$a = $b $a;" is performed, the value of "$a" becomes 13, and the value of "$b" does not change. Changes have occurred. After we have a certain understanding of this operator, let's take a look at the basic assignment operator.

The value of the assignment expression is the assignment. Its function is to assign the value of an expression to an lvalue. An expression is an lvalue or lvalue. The so-called lvalue refers to an expression that can be used on the left side of an assignment operation. The lvalue must be modifiable and cannot be a constant. We use variables as lvalues. We can also see that pointers and references can also be lvalues.

Note: The assignment operation copies the value of the original variable to the new variable (value assignment), so changing one variable does not affect the other variable. This also works for copying certain values ​​in dense loops, such as large arrays.

There is an exception to the common value-passing and assignment behavior in PHP, which is when an object is encountered, which in PHP 5 is assigned by reference unless copied explicitly using the clone keyword.

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