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灭绝师太Correction status：qualified
Teacher's comments：
Collection
Collection
1.// 给定一个数组$arr = [23,3,45,6,78,8,34],筛选其偶数成员组成新的数组返回，请封装函数。```php
<?php
$arr = [23,3,45,6,78,8,34];
function shaixuan($arr){
foreach($arr as $k =>$v){
if($k % 2 == 0){
$newArr[]=$v;
}
}
return $newArr;
}
var_dump(shaixuan($arr));
?>
2. 尝试实现简单的计算器功能，语言不限制。```php<?php$num1 = $_GET['num1'] ?? '请输入第一个数';$num2 = $_GET['num2'] ?? '请输入第二个数';$ysf = $_GET['con'] ?? '请选择运算符';$result= '';if (isset($ysf)){if ($ysf== '*'){$result = $num1 * $num2;}if($ysf == '/'){if($num2 != 0){$result = $num1 / $num2;}else{$result = '除数不能为零';}}if($ysf == '+'){$result =$num1 + $num2;}if($ysf == '-'){$result = $num1 - $num2;}}?><!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>计算器</title></head><body><form action="" method="get"><input type="text" name= "num1"><br><select name="con"><option value="+">+</option><option value="-">-</option><option value="*">*</option><option value="/">/</option><input type="text" name= "num2" ><br><input type="submit" value="计算"><br></form></body></html><?= $result?>