PHP switch语句 _条件语句

本文概述

带字符的PHP switch语句
带String的PHP switch语句
PHP switch语句失败
PHP嵌套switch语句

PHP switch语句用于从多个条件执行一个语句。它的工作原理类似于PHP if-else-if语句。
句法

switch(expression){ case value1: //code to be executed break; case value2: //code to be executed break; ...... default: code to be executed if all cases are not matched; }

有关开关盒的注意事项：

默认值为可选语句。即使不重要, 默认值也必须始终是最后一条语句。
switch语句中只能有一个默认值。多个默认值可能导致致命错误。
每个案例可以有一个break语句, 该语句用于终止语句序列。
break语句在switch中是可选的。如果不使用break, 所有语句将在找到匹配的case值后执行。
PHP允许你在开关表达式中使用数字, 字符, 字符串以及函数。
允许嵌套switch语句, 但这会使程序更复杂, 可读性更差。
你可以使用分号(; )代替冒号(:)。它不会产生任何错误。

PHP切换流程图

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PHP Switch示例

< ?php $num=20; switch($num){ case 10: echo("number is equals to 10"); break; case 20: echo("number is equal to 20"); break; case 30: echo("number is equal to 30"); break; default: echo("number is not equal to 10, 20 or 30"); } ?>

输出

number is equal to 20

带字符的PHP switch语句检查元音和辅音的程序
我们将在switch表达式中传递一个字符, 以检查它是元音还是常量。如果传递的字符是A, E, I, O或U, 则它是元音, 否则是辅音。

< ?php $ch = 'U'; switch ($ch) { case 'a': echo "Given character is vowel"; break; case 'e': echo "Given character is vowel"; break; case 'i': echo "Given character is vowel"; break; case 'o': echo "Given character is vowel"; break; case 'u': echo "Given character is vowel"; break; case 'A': echo "Given character is vowel"; break; case 'E': echo "Given character is vowel"; break; case 'I': echo "Given character is vowel"; break; case 'O': echo "Given character is vowel"; break; case 'U': echo "Given character is vowel"; break; default: echo "Given character is consonant"; break; } ?>

输出

Given character is vowel

带String的PHP switch语句 PHP允许在开关表达式中传递字符串。让我们通过在switch case语句中传递字符串来查看下面的课程持续时间示例。

< ?php $ch = "B.Tech"; switch ($ch) { case "BCA": echo "BCA is 3 years course"; break; case "Bsc": echo "Bsc is 3 years course"; break; case "B.Tech": echo "B.Tech is 4 years course"; break; case "B.Arch": echo "B.Arch is 5 years course"; break; default: echo "Wrong Choice"; break; } ?>

输出

B.Tech is 4 years course

PHP switch语句失败 【PHP switch语句】PHP switch语句失败。这意味着如果未找到break语句, 它将在获得第一个匹配项后执行所有语句。

< ?php $ch = 'c'; switch ($ch) { case 'a': echo "Choice a"; break; case 'b': echo "Choice b"; break; case 'c': echo "Choice c"; echo "< /br> "; case 'd': echo "Choice d"; echo "< /br> "; default: echo "case a, b, c, and d is not found"; } ?>

输出

Choice c Choice d case a, b, c, and d is not found

PHP嵌套switch语句嵌套的switch语句意味着switch语句位于另一个switch语句内。有时会导致混乱。

< ?php $car = "Hyundai"; $model = "Tucson"; switch( $car ) { case "Honda": switch( $model ) { case "Amaze": echo "Honda Amaze price is 5.93 - 9.79 Lakh."; break; case "City": echo "Honda City price is 9.91 - 14.31 Lakh."; break; } break; case "Renault": switch( $model ) { case "Duster": echo "Renault Duster price is 9.15 - 14.83 L."; break; case "Kwid": echo "Renault Kwid price is 3.15 - 5.44 L."; break; } break; case "Hyundai": switch( $model ) { case "Creta": echo "Hyundai Creta price is 11.42 - 18.73 L."; break; case "Tucson": echo "Hyundai Tucson price is 22.39 - 32.07 L."; break; case "Xcent": echo "Hyundai Xcent price is 6.5 - 10.05 L."; break; } break; } ?>

输出