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0805 一.将数组的偶数去出, 二.尝试实现计算器功能
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一.将数组的偶数去出, 二.尝试实现计算器功能

一.将一个数组中的偶数取出

方法一 用过滤器的方法

  1. <?php
  2. $arr = [3,5,6,9,15,18,22];
  3. function demo($sum)
  4. {
  5.     return !($sum % 2); //声明一个函数,返回取余等于零的为ture
  6. }
  7. $sum1= array_filter($arr,'demo');//将数组中返回为ture的保存到一个新数组中
  8. var_dump($sum1);

方法二 用数组遍历的方法

  1. <?php
  2. $arr = [12,15,18,21,26,30,33,46];
  4. function arr1($number)
  5. {
  6.     $arrDouble=[];
  7.     foreach($number as $arr2)
  8.     {
  9.     //将数组中的成员,取余为0为FLASE,然后去反为TRUE,返回为TURE的成员通过入列的方式传到一个新数组中
  10.         if (!($arr2 % 2)) array_push($arrDouble,$arr2); 
  11.     }
  12.     return $arrDouble;
  13.    //函数返回一个装有偶数的新数组
  14. }
  15. print_r(arr1($arr));

二.尝试实现一个计算器功能

  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <meta http-equiv="X-UA-Compatible" content="IE=edge">
  6.     <meta name="viewport" content="width=device-width, initial-scale=1.0">
  7.     <title>尝试实现一个计算机功能</title>
  10. </head>
  11. <?php
  12.     $error="";
  13.     $num1 = $_POST["num1"] ?? "";
  14.     $num2 = $_POST["num2"] ?? "";
  15.     $operator = $_POST["operator"] ?? "";
  16.     if(isset( $_POST["sub"])){
  17.         if($num1 == ""){
  18.             $error .= "请输入第一个数据";
  19.         }elseif(!is_numeric($num1)){
  20.             $error .= "必须是数字";
  21.         }
  22.         if($num2 == ""){
  23.             $error .=  "请输入第二个数据";
  24.         }elseif(!is_numeric($num2)){
  25.             $error .= "必须为数字";
  26.         }
  28.         if(($operator == '/' || $operator == '%') && $num2 == 0)
  29.         {
  30.             $error .= "被除数不能为0";
  31.         }
  32.     }
  33. ?>
  34. <body>
  35.     <table align="center" border="1" width="600" >
  36.         <caption><h2>计算器</h2></caption>
  37.         <form action=""method="post">
  38.             <tr>
  39.                 <td>
  40.                     <input type="text" name="num1" value="<?php echo $num1 ?>">
  41.                 </td>
  42.                 <td>
  43.                     <select name="operator">
  44.                         <option value="+" <?php if($operator == "+") echo "selected"?>>+</option>
  45.                         <option value="-" <?php if($operator == "-") echo "selected"?>>-</option>
  46.                         <option value="*" <?php if($operator == "*") echo "selected"?>>*</option>
  47.                         <option value="/" <?php if($operator == "/") echo "selected"?>>/</option>
  48.                         <option value="%" <?php if($operator == "%") echo "selected"?>>%</option>
  49.                     </select>
  50.                 </td>
  51.                 <td>
  52.                     <input type="text" name = "num2" value="<?php echo $num2 ?>" >
  53.                 </td>
  54.                 <td>
  55.                     <input type="submit" name="sub" value="计算">
  56.                 </td>
  57.             </tr>
  60.     <?php 
  61.         if(isset($_POST["sub"])){
  62.             echo '<tr><td colspan = "5" align ="center">';
  63.                 if(empty($error)){
  64.                     $sum = 0;
  65.                     switch($operator){
  66.                         case "+":
  67.                             $sum = $num1 + $num2 ;
  68.                             break;
  69.                         case "-":
  70.                             $sum = $num1 - $num2 ;
  71.                             break;
  72.                         case "*":
  73.                             $sum = $num1 * $num2 ;
  74.                             break;
  75.                         case "/":
  76.                             $sum = $num1 / $num2;
  77.                             break;
  78.                         case "%":
  79.                             $sum = $num1 % $num2;
  80.                             break;
  81.                 }
  82.                 echo "结果: {$num1} {$operator} {$num2} = {$sum} ";
  83.             }else{ echo $error;}
  85.             echo '</td></tr>';
  86.         }
  87.         ?>
  88.             </form>
  89.         </table>
  90.     </body>
  91. </html>
Correcting teacher：PHPzPHPz

Correction status：qualified

Teacher's comments：
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