<?php$pen = ["红","蓝","蓝","红","红","蓝","红","蓝","红","红","红","蓝","红","黄","蓝","其他","其他"]; // 所有的铅笔$redNum = 0; // 赤色铅笔数$yellowNum = 0; // 黄色铅笔数$blueNum = 0; // 蓝色铅笔数$otherNum = 0;foreach($pen as $val){ if($val=="红"){ $redNum++; }else if($val=="黄"){ $yellowNum++; }else if($val=="蓝"){ $blueNum++; }else{ $otherNum++; }}echo "赤色铅笔数：".$redNum.PHP_EOL;echo "黄色铅笔数：".$yellowNum.PHP_EOL;echo "蓝色铅笔数：".$blueNum.PHP_EOL;echo "其他颜色铅笔数：".$otherNum.PHP_EOL;?>
以下会输出：
赤色铅笔数：8黄色铅笔数：1蓝色铅笔数：6其他颜色铅笔数：2
如果有100多种颜色的话，怎么办？难道写100个if和else判断么？当然弗成，那样写下来，代码太不随意马虎理解了，看下面的例子：
<?php$pen = ["红","蓝","蓝","红","红","蓝","红","蓝","红","红","红","蓝","红","黄","蓝","其他","其他"]; // 所有的铅笔$redNum = 0; // 赤色铅笔数$yellowNum = 0; // 黄色铅笔数$blueNum = 0; // 蓝色铅笔数$otherNum = 0;foreach($pen as $val){ switch($val) { case "红": $redNum++; break; case "黄": $yellowNum++; break; case "蓝": $blueNum++; break; default: $otherNum++; break; }}echo "赤色铅笔数：".$redNum.PHP_EOL;echo "黄色铅笔数：".$yellowNum.PHP_EOL;echo "蓝色铅笔数：".$blueNum.PHP_EOL;echo "其他颜色铅笔数：".$otherNum.PHP_EOL;?>
输出：
赤色铅笔数：8黄色铅笔数：1蓝色铅笔数：6其他颜色铅笔数：2
和上面的输出一样。
注：switch($val)表示取出$val的值，case "红":表示$val如果是"红"，default:表示没有匹配到的红，黄，蓝的其他选项的情形
