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HomeBackend DevelopmentPHP TutorialPHP Switch 语句之学习笔记_PHP

PHP 中的 Switch 语句用于执行基于多个不同条件的不同动作。

Switch 语句

如果您希望有选择地执行若干代码块之一,请使用 Switch 语句。

使用 Switch 语句可以避免冗长的 if..elseif..else 代码块。

语法

复制代码 代码如下:
switch (expression)
{
case label1:
code to be executed if expression = label1;
break;
case label2:
code to be executed if expression = label2;
break;
default:
code to be executed
if expression is different
from both label1 and label2;
}


实例

工作原理:

对表达式(通常是变量)进行一次计算
把表达式的值与结构中 case 的值进行比较
如果存在匹配,则执行与 case 关联的代码
代码执行后,break 语句阻止代码跳入下一个 case 中继续执行
如果没有 case 为真,则使用 default 语句

复制代码 代码如下:
switch ($x)
{
case 1:
echo "Number 1";
break;
case 2:
echo "Number 2";
break;
case 3:
echo "Number 3";
break;
default:
echo "No number between 1 and 3";
}
?>

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