PHP Switch語(yǔ)句
PHP switch語(yǔ)句用于從多個(gè)條件中執(zhí)行一條語(yǔ)句。愛掏網(wǎng) - it200.com它的工作方式類似于PHP的if-else-if語(yǔ)句。愛掏網(wǎng) - it200.com
語(yǔ)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;
}
關(guān)于switch case的重要注意事項(xiàng)
- default 是可選語(yǔ)句。愛掏網(wǎng) - it200.com即使不重要，default必須始終是最后一個(gè)語(yǔ)句。愛掏網(wǎng) - it200.com
- switch語(yǔ)句中只能有一個(gè) default 。愛掏網(wǎng) - it200.com多個(gè)default可能導(dǎo)致 致命錯(cuò)誤 。愛掏網(wǎng) - it200.com
- 每個(gè)case可以有一個(gè) break 語(yǔ)句，用于終止語(yǔ)句序列。愛掏網(wǎng) - it200.com
- 在switch中， break 語(yǔ)句是可選的。愛掏網(wǎng) - it200.com如果不使用break，所有與匹配case值相對(duì)應(yīng)的語(yǔ)句都會(huì)執(zhí)行。愛掏網(wǎng) - it200.com
- PHP允許在switch表達(dá)式中使用數(shù)字、字符、字符串和函數(shù)。愛掏網(wǎng) - it200.com
- 允許嵌套switch語(yǔ)句，但會(huì)使程序變得更復(fù)雜且不易閱讀。愛掏網(wǎng) - it200.com
- 你可以使用分號(hào)(;)代替冒號(hào)(:)，不會(huì)產(chǎn)生任何錯(cuò)誤。愛掏網(wǎng) - it200.com
PHP Switch流程圖
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");
}
?>
輸出：
number is equal to 20
PHP字符的switch語(yǔ)句
檢查元音和輔音的程序
我們將傳遞一個(gè)字符給switch表達(dá)式來(lái)檢查它是元音還是輔音。愛掏網(wǎng) - it200.com如果傳遞的字符是A、E、I、O或U，它將是元音，否則是輔音。愛掏網(wǎng) - it200.com
<?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;
}
?>
輸出：
Given character is vowel
PHP中的字符串 switch 語(yǔ)句
PHP允許在switch表達(dá)式中傳遞字符串。愛掏網(wǎng) - it200.com讓我們通過在switch case語(yǔ)句中傳遞字符串來(lái)看下面的課程時(shí)長(zhǎng)示例。愛掏網(wǎng) - it200.com
<?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;
}
?>
輸出：
B.Tech is 4 years course
PHP的switch語(yǔ)句是穿透的
PHP的switch語(yǔ)句是穿透的。愛掏網(wǎng) - it200.com這意味著在找到第一個(gè)匹配項(xiàng)后，如果沒有找到break語(yǔ)句，它將執(zhí)行所有的語(yǔ)句。愛掏網(wǎng) - it200.com
<?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";
}
?>
輸出：
Choice c
Choice d
case a, b, c, and d is not found
PHP嵌套的switch語(yǔ)句
嵌套的switch語(yǔ)句意味著在另一個(gè)switch語(yǔ)句內(nèi)部使用switch語(yǔ)句。愛掏網(wǎng) - it200.com有時(shí)會(huì)導(dǎo)致混淆。愛掏網(wǎng) - it200.com
<?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;
}
?>
輸出：
Hyundai Tucson price is 22.39 - 32.07 L.
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