请教一个 PHP 代码出错的原因（一个简单的计算器）

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代码如下：

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>a small calculate</title>
</head>
<body>

<form>

<input type="text" name="num1" placeholder="number 1">
<input type="text" name="num2" placeholder="number 2">
<select name="operator">
<option>None</option>
<option>Add</option>
<option>Subtract</option>
<option>Multiply</option>
<option>Divide</option>
</select>
<br>
<button name="submit" value="good submit" type="submit" >Calculate</button>

</form>

<p>the answer is:</p>

<?php

if(isset($_GET['submit'])){
$result1 = $_GET('num1');
$result2 = $_GET('num2');
$operator = $_GET('operator');

switch($operator){
case "None":
echo "Error,you need select a method.";
break;

case "Add":
echo $result1 + $result2;
break;

case "Subtract":
echo $result1 - $result2;
break;

case "Multiply":
echo $result1 * $result2;
break;

case "Divide":
echo $result1 / $result2;
break;

}

}

?>

</body>
</html>

运行后测试：文本框输入值后，点击 calculate 按钮返回错误：

Fatal error: Function name must be a string in /Applications/XAMPP/xamppfiles/htdocs/calculate.php on line 29

请问如何解决呢？

代码片段：

28 行 if(isset($_GET['submit'])){
29 行 $result1 = $_GET('num1');
30 行 $result2 = $_GET('num2');
31 行 $operator = $_GET('operator');

option

result2

result1

get

10 replies • 2019-02-08 17:54:42 +08:00

898684526

Feb 6, 2019

获取 get 参数应该是 [] 而不是()

caola

Feb 6, 2019

$_GET 获取的数据并不存在，先判断是否存在： $result1 = $_GET('num1') ?? 0;

898684526

Feb 6, 2019

你从 29 行 $_GET('num1') 应该是 $_GET['num1'];

caola

Feb 6, 2019

确实是方括号问题（上面我直接复制了）

clf

Feb 6, 2019

$_GET['xxx'] 不是 $_GET('xxx')

githere

Feb 6, 2019

@898684526 @caola @lychs1998 感谢各位，我真是眼瞎啊！！

Hardrain

Feb 6, 2019

var_dump($_GET)可知其为数组，应使用$_GET['parameter']

$_POST $_SERVER $_COOKIE 等也是数组

orqzsf1

Feb 6, 2019

<select>
<option value ="volvo">Volvo</option>
<option value ="saab">Saab</option>
<option value="opel">Opel</option>
<option value="audi">Audi</option>
</select>

githere

Feb 7, 2019

@898684526 @caola @lychs1998 追问一下，请问如何理解这一行代码的意思：

if(isset($_GET['submit'])) {}

bzj

Feb 8, 2019

楼主把这里当百度知道了，基础不好不去学习，跑来这里问，习惯不好