Simple comparison of PHP operators "and" and "&&"

In PHP, "and" and "&&" are both used as logical operators and perform the same operation. So what is the difference between them? This article will give you a brief introduction to the operators "and" and "&&" so that you can understand the difference between the operators "and" and "&&". I hope it will be helpful to you.

"and" operator

In the "and" operator, if two If both operands are true, return true; if one of the operands is false, return false. Example:

<?php 
// 变量声明和初始化
$a = 100; 
$b = 10; 
  
//使用"and"运算符
if ($a == 100 and $b == 10) 
    echo "结果为：true"; 
else
    echo "结果为：false"; 
?>

Output:

Description:

Since variable $a = 100 and another variable $b = 10, the condition $a == 100 evaluates to true, while $b == 10 evaluates to true. Because the and logic says that the result is only true if both operands are true; therefore, '$a == 100 and $b == 10' evaluate to true.

But when $b = 20 is input, the condition $b == 10 will be false, so the AND operation result will be false.

"&&" operator

In the "&&" operator, if both operands are true, true will be returned. ;If one is false, return false. Example:

<?php 
// 声明变量并初始化它
$a = 100; 
$b = 10; 
  
// 使用
if ($a == 100 && pow($b, 2) == $a) 
    echo "结果为：true"; 
else
    echo "结果为：false"; 
?>

Output:

Description:

Since variable $a = 100 and another variable $b = 10, the condition $a == 100 evaluates to true, and pow($b,2) == $a also evaluates to true, because $b = 10 raised to the power of 2 is 100, which is equal to $a.

And logic indicates that the result of the AND operation is true only when both operands are true. So the expression '$a == 100 && pow($b, 2) == $a' evaluates to true.

But when $b = 20, the result of the condition pow ($b, 2) == $a is false, so the result of the and operation will become false.

A simple comparison between operators "and" and "&&"

There are some differences between operators "and" and "&&" Difference: The "&&" operator has high precedence, while the "and" operator has low precedence.

Description: Priority basically determines which operations are performed first in an expression.

Let’s take a look at the differences between operators "and" and "&&" through a simple code example.

<?php 
// 在表达式中使用&&运算符
$bool = true && false; 

// 显示&&运算符的运算结果
echo "&&运算符的结果为：";
echo ($bool ? &#39;true&#39; : &#39;false&#39;), "<br><br>"; 
 
// 在表达式中使用and运算符
$bool = true and false; 
// 显示and运算符的运算结果
echo "and运算符的结果为：";
echo ($bool ? &#39;true&#39; : &#39;false&#39;);  
?>

Output:

We also found that when the operands of the two operators are the same, their operation results are different. Why?

Because the "&&" operator has a higher priority than the "=" operator; and the "and" operator has a lower priority than the "=" operator.

In the first expression "$bool = true && false", first calculate true && false, the calculation result is false, and then assign this result to $bool; therefore, the value of $bool is : false.

In the second expression "$bool = true and false", first execute "$bool = true", at which time the value of $bool is true; then execute "$bool and false". Because the "and" operation is performed internally but not allocated, the value of $bool is still true.

Summary: The fundamental difference between the PHP operators "and" and "&&" lies in their priority difference; the above is the entire content of this article, I hope it can be helpful to everyone's learning helped.

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