Php 多选择阵列

试试这个

Name
hello jimbo1qaz
3 Array

Notice: Undefined variable: colors in E:\xampp\htdocs\myform.php on line 28

Notice: Undefined index: in E:\xampp\htdocs\myform.php on line 28 is your first color.
Notice: Undefined variable: colors in E:\xampp\htdocs\myform.php on line 29

1.
2.
3.
4.
5.

此时$\u GET以数组形式显示，您没有正确引用键，它是一个字符串而不是一个变量。请参见下文

print_r($_GET["colors"]);

---

为什么要使用

$colors

变量，比如

$\u GET[$colors[0]]

。这不是一个变量。而不是像这样使用：

  <?php
            $number=10;
            echo "hello";
            if (isset($_GET["name"])){
                echo " ".$_GET["name"];
                echo "<br />";
            }
            echo count($_GET["colors"]), " ", $_GET["colors"], "<br />";
            echo $_GET["colors"][0]," is your first color.";
            if(isset($_GET["colors"])){
                echo "You must like ";
                for($colornum=0;$colornum<count($_GET["colors"]);$colornum++){
                    echo $_GET["colors"][$colornum]," ";
                }
            }
        ?>

如果您单击我名字上方的“x分钟前”，您可以看到更改（我更改了输出的设计）。

//this should be $_GET['colors'][0]
echo $_GET[$colors[0]]," is your first color.";   

//the , is wrong, you need to use . (point)
echo $_GET[$colors[0]]," is your first color."; 

//Delete the $
if(isset($_GET["$colors"])){  

//it's $_GET['colors']
for($colornum=0; $colornum<count($_GET["$colors"]); $colornum++){    
    //Here you need to use $_GET['colors'][$colornum]
    echo $_GET[$colors[$colornum]]," ";    
}  

print_r($_GET["colors"]);

  <?php
            $number=10;
            echo "hello";
            if (isset($_GET["name"])){
                echo " ".$_GET["name"];
                echo "<br />";
            }
            echo count($_GET["colors"]), " ", $_GET["colors"], "<br />";
            echo $_GET["colors"][0]," is your first color.";
            if(isset($_GET["colors"])){
                echo "You must like ";
                for($colornum=0;$colornum<count($_GET["colors"]);$colornum++){
                    echo $_GET["colors"][$colornum]," ";
                }
            }
        ?>

$_GET['colors'][0]