How to solve the problem of array index not found in php7

php7 cannot find the solution to the array index: 1. Create a PHP sample file; 2. Define the array variable $my_array; 3. Use the isset() or array_key_exists() function to check through the if judgment statement. Check whether the specified index exists in the array; 4. Just output the corresponding result or error message.

Operating system for this tutorial: Windows 10 system, php8.1.3 version, Dell G3 computer.

When a PHP program encounters a situation where the array index cannot be found (that is, the index does not exist in the array), a "Notice" level error message is usually thrown.

To solve this problem, you can use isset() or array_key_exists() function to check whether the specified index exists in the array.

The following is a code example:

// 定义一个数组
$my_array = array(
    'apple' => 'red',
    'banana' => 'yellow',
    'orange' => 'orange'
);
// 判断数组是否存在指定的键
if(isset($my_array['grape'])) {
    // 存在，则访问该元素
    echo $my_array['grape'];
} else {
    // 不存在，则提示用户或进行其他操作
    echo "Sorry, no grape found!";
}
// 或者使用array_key_exists()函数
if(array_key_exists('pear', $my_array)) {
    // 存在，则访问该元素
    echo $my_array['pear'];
} else {
    // 不存在，则提示用户或进行其他操作
    echo "Sorry, no pear found!";
}

In the above example, an array containing three elements is defined. We then used the isset() and array_key_exists() functions to check whether the two indexes "grape" and "pear" exist in the array respectively. If it exists, access the element, otherwise output the corresponding error message.

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