PHP循环控制,for，while遍历关联数组

一、PHP循环控制

数组指针

1、key():返回当前数组元素的键
2、current():返回当前数组元素的值
3、next():将指针指向数组元素当前元素的下一个元素的位置
4、reset():复位数组指针，指向第一个元素
5、prev():数组指针上移一个
6、end():数组指针移到最后一个元素

PHP循环控制、`for()`、`while()`遍历数组

<?php
/*php循环控制-遍历索引数组*/
$arr1 = ['van', 'toan', 'anh', 'ly', 'hoa hoc'];
//for()
for($i = 0; $i < count($arr1); $i++ ) {
    echo $arr1[$i] .',';
}
echo '<hr>';
//while()
$i = 0;
while ($i < count($arr1)) {
    echo $arr1[$i] .',';
    $i++;
}
echo '<hr>';
//foreach
 foreach($arr1 as $value) {
     echo $value . '<br>';
 }
 echo '<hr>';
/*for()、while()遍历关联数组*/
$arr2 = ['quocgia' =>'vietnam', 'thudo' => 'hanoi', 'dantoc' => 'kinh', 'danso' => '100000000', 'trungtam' => 'haiphong'];
//for()
for($i = 0; $i < count($arr2); $i++){
    echo key($arr2) . '==>' . current($arr2) . '<br>';
    next($arr2);
}
echo '<hr>';
//while()
reset($arr2);
while (current($arr2)) {
    echo key($arr2) . '+++>' . current($arr2) . '<br>';
    next($arr2);
}
echo '<hr>';
//foreach()
foreach ($arr2 as $key => $value) {
    echo "$key => $value <br>";
}
echo '<hr>';

二、表单验证

HTML代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>表单验证</title>
    <style>
        .register > form{
            width: 400px;
            height: 300px;
            background-color: #19c0e7;
            border-radius: 10px; /*圆角*/
            text-align: center;
            margin: auto;
        }
        .register > form > div {
            display: grid;
            grid-template-columns: 100px 200px;
            margin: 20px 0;
            grid-column-gap:10px;
        }
        .register > form > div > label{
            text-align: right;
        }
        .register > form > div > input{
            border-radius: 5px;
        }
    </style>
</head>
<body>
<div class="register">
    <form action="action.php" method="post">
        <h3>用户注册</h3>
        <div>
            <label for="username">用户名</label>
            <input type="text" name="username" id="username" placeholder="不超过20个字符" required autofocus>
        </div>
        <div>
            <label for="password1">密码</label>
            <input type="password" name="password1" id="password1" placeholder="不能为空" required>
        </div>
        <div>
            <label for="password2">重复密码</label>
            <input type="password" name="password2" id="password2" placeholder="再次输入的密码必须一致。" required>
        </div>
        <div>
            <label for="email">邮箱</label>
            <input type="email" name="email" id="email" placeholder="不能为空" required>
        </div>
        <span>
            <button>提交</button>
        </span>
    </form>
</div>
</body>
</html>

HTML效果

PHP代码：

<?php
if ($_SERVER['REQUEST_METHOD'] === 'POST') { /*判断请求类型*/
//    echo 'YES';
    //empty():判断一个变量是否为“空”,当一个变量值为0，empty() 认为这个变量同等于空，即相当于没有设置。
    if(!empty($_POST['username'])) $username = $_POST['username'];
    if(!empty($_POST['password1'])) $password1 = $_POST['password1'];
    if(!empty($_POST['password2'])) $password2 = $_POST['password2'];
    if(!empty($_POST['email'])) $email = $_POST['email'];
    if ($password1 === $password2) {
        $password = md5(sha1($password1));
    }else{
        exit('<script>alert("两次密码不一致。"); history.back();</script>');
    }
    //compact（）：将得到的变量压缩到一个数组
    $data = compact('username', 'password', 'email');
    if((print($data)) === 1){
        exit('<script>alert("注册成功，请登录。"); history.back();</script>');
    }else{
        exit('<script>alert("注册失败，请登重试。"); history.back();</script>');
    }
}else{
    exit('<h3 style="color: red">请求类型错误！</h3>');
}