Detailed analysis of switch statement in php

We all know that the switch statement is a loop statement, used to perform different actions based on different conditions. The Switch statement is also the longest and most common logic in Object-orientedprogramming statements The control statement is . Switch statements are used to perform different actions based on multiple different conditions - that is, when the conditions are different, different logical operations are performed.

This article introduces the usage of the switch statement in PHP. It is similar to the switch usage in other statements, but note that there is a break statement.

Standard syntax of switch statement in PHP:

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;
}

Example:

switch($i){
  case 1:
    echo 1;
    break;
  case 2:
    echo 2;
    break;
  default:
    echo 'others';
}

You can also use switch to determine a value range, or Customize conditions in case.

<?php
header("content-type:text/html;charset=utf8");
$score=50;
switch($score) 
{
 case $score>=90 && $score<=100:
  echo "优<br>";
  break;
 case $score>=80 && $score<90:
  echo "良<br>";
  break;
 case $score>=70 && $score<80:
  echo "中<br>";
  break;
 case $score>=60 && $score<70:
  echo "及格<br>";
  break;
 case $score>=0 && $score<60:
  echo "不及格<br>";
  break;
 default:
  echo"成绩输入错误<br>";
}
?>

Simple example

<?php 
 //switch细节 
 //情况一：数值匹配的时候自动转换成字串 
 $a=1; 
 switch($a){ 
  case "1": 
    echo &#39;hello1&#39;; 
    break; 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
  //情况二：数值匹配的时候自动转换成字符 
 $a=1; 
 switch($a){ 
  case &#39;1&#39;: 
    echo &#39;hello2&#39;; 
    break; 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
  //情况三：字符匹配的时候自动转换成数值 
 $a=&#39;1&#39;; 
 switch($a){ 
  case 1: 
    echo &#39;hello3&#39;; 
    break; 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
  //情况四：字串匹配的时候自动转换成数值 
 $a="1"; 
 switch($a){ 
  case 1: 
    echo &#39;hello4&#39;; 
    break; 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
  //情况五：float也可以匹配 
 $a=1.1; 
 switch($a){ 
  case 1.1: 
    echo &#39;hello5&#39;; 
    break; 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
  //情况六：非0是true 
 $a=true; 
 switch($a){ 
  case 1: 
    echo &#39;hello6&#39;; 
    break; 
  case true: 
    echo &#39;hello61&#39;; 
    break; 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
  //情况七：能匹配boolean 
 $a=true; 
 switch($a){ 
  case true: 
    echo &#39;hello7&#39;; 
    break; 
  case 2: 
    echo &#39;hello71&#39;; 
    break; 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
  //情况八：能匹配null 
 $a=null; 
 switch($a){ 
  case 2://&#39;&#39; "" false 0 都能进入 
    echo &#39;hello8&#39;; 
    break; 
  case null: 
    echo &#39;hello81&#39;; 
    break; 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
  //情况九：退出顺序 
 $a=5; 
 switch($a){ 
  case 1: 
    echo &#39;hello6&#39;; 
    break; 
  case 2: 
    echo &#39;我是2号出口&#39;; 
    break; 
  case 5: 
    echo &#39;我是5号出口&#39;; 
    //break; 
  case true: 
    echo &#39;hello61&#39;; 
    break; 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
  //情况十：退出顺序 
 $a=50; 
 switch($a){ 
  default: 
    echo &#39;sorry none is the same!&#39;; 
    //break; 
  case 50: 
    echo &#39;hello6&#39;; 
    //break; 
  case 2: 
    echo &#39;我是2号出口&#39;; 
    break; 
  case 5: 
    echo &#39;我是5号出口&#39;; 
    //break; 
  case 6: 
    echo &#39;hello61&#39;; 
    break; 
 } 
 echo &#39;<br/>&#39;.&#39;成功退出····&#39;; 
 echo &#39;<hr/>&#39;; 
?>

Running results

hello1
成功退出····
hello2
成功退出····
hello3
成功退出····
hello4
成功退出····
hello5
成功退出····
hello6
成功退出····
hello7
成功退出····
hello81
成功退出····
我是5号出口hello61
成功退出····
hello6我是2号出口
成功退出····

Summary:

This article uses detailed examples This article explains the switch statement in PHP to give you a more intuitive understanding. I believe you all have a preliminary understanding of the switch statement!

Related recommendations:

php switch statement syntax example and efficiency comparison with ifelse

php switch statement basic syntax example detailed explanation

php switch statementBasic Use and extend using

The above is the detailed content of Detailed analysis of switch statement in php. For more information, please follow other related articles on the PHP Chinese website!