Php ошибка undefined offset

Notice: Undefined offset

This error means that within your code, there is an array and its keys. But you may be trying to use the key of an array which is not set.

The error can be avoided by using the isset() method. This method will check whether the declared array key has null value or not. If it does it returns false else it returns true for all cases.

This type of error occurs with arrays when we use the key of an array, which is not set.

In the following, given an example, we are displaying the value store in array key 1, but we did not set while declaring array “$colorarray.”

Error Example:

<?php
// Declare an array with key 2, 3, 4, 5
$colorarray = array(2=>'Red',3=>'Green',4=>'Blue',5=>'Yellow');
// Printing the value of array at offset 1.
echo $colorarray[1];
?>

Output:

Notice: Undefined offset: 1 in index.php on line 5

Here are two ways to deal with such notices.

1. Resolve such notices.
2. Ignore such notices.

Fix Notice: Undefined offset by using isset() Function

Check the value of offset array with function isset(), empty(), and array_key_exists() to check if key exist or not.

Example:

<?php
$colorarray = array(2=>'Red',3=>'Green',4=>'Blue',5=>'Yellow');
// isset() function to check value at offset 1 of array
if(isset($colorarray[1])){echo $colorarray[1];}
// empty() function to check value at offset 1 of array
if(!empty($colorarray[1])){echo $colorarray[1];}
// array_key_exists() of check if key 1 is exist or not
echo array_key_exists(1, $colorarray);
?>

How to Ignore PHP Notice: Undefined offset?

You can ignore this notice by disabling reporting of notice with option error_reporting.

1. Disable Display Notice in php.ini file

Open php.ini file in your favourite editor and search for text “error_reporting” the default value is E_ALL. You can change it to E_ALL & ~E_NOTICE.

By default:

error_reporting = E_ALL

Change it to:

error_reporting = E_ALL & ~E_NOTICE

Now your PHP compiler will show all errors except ‘Notice.’

2. Disable Display Notice in PHP Code

If you don’t have access to make changes in the php.ini file, In this case, you need to disable the notice by adding the following code on the top of your php page.

<?php error_reporting (E_ALL ^ E_NOTICE); ?>

Now your PHP compiler will show all errors except ‘Notice.’

Before discovering how to avoid the PHP undefined offset error, let’s see what it is. The undefined offset is the one that doesn’t exist inside an array. An attempt to access such an index will lead to an error, which is known as undefined offset error.

Let’s see an example:

<?php

// Declare and initialize an array
// $students = ['Ann', 'Jennifer', 'Mary']
$students = [
    0 => 'Ann',
    1 => 'Jennifer',
    2 => 'Mary',
];

// Leyla
echo $students[0];

// ERROR: Undefined offset: 5
echo $students[5];

// ERROR: Undefined index: key
echo $students[key];

?>

Below, we will show you several methods to avoid the undefined offset error.

This function allows checking if the variable is set and is not null.

The example of using the isset function to avoid undefined offset error is as follows:

<?php

// Declare and initialize an array
// $students = ['Ann', 'Jennifer', 'Mary']
$students = [
    0 => 'Ann',
    1 => 'Jennifer',
    2 => 'Mary',
];

if (isset($students[5])) {
    echo $students[5];
} else {
    echo "Index not present";
}

?>

Index not present

The empty() function is used for checking if the variable or the index value inside an array is empty.

Here is an example:

<?php

// Declare and initialize an array
// $students = ['Rohan', 'Arjun', 'Niharika']
$students = [
  0 => 'Ann',
  1 => 'Jennifer',
  2 => 'Mary',
];

if (!empty($students[5])) {
  echo $students[5];
} else {
  echo "Index not present";
}

?>

Index not present

This function is used for associative arrays that store data in the key-value pair form, and there is a value for each key.

The array_key_exists function is used for testing if a particular key exists in an array or not.

Here is an example:

<?php
// PHP program to illustrate the use
// of array_key_exists() function

function Exists($index, $array)
{
    if (array_key_exists($index, $array)) {
        echo "Key Found";
    } else {
        echo "Key not Found";
    }
}

$array = [
    "john" => 25,
    "david" => 10,
    "jack" => 20,
];

$index = "jack";

print_r(Exists($index, $array));

?>

Key Found

Приветствую! Посмотрел в логе есть несколько ошибок, помогите исправить пожалуйста, спасибо!

error.log

[Sun Jan 27 08:42:09.476142 2019] [fcgid:warn] [pid 28535] mod_fcgid: stderr: PHP Notice: Only variables should be passed by reference in /var/www/mysite/data/www/mysite.io/core/Classes/Lang.php on line 90

[Sun Jan 27 08:42:09.476145 2019] [fcgid:warn] [pid 28535] mod_fcgid: stderr: PHP Notice: Undefined offset: 1 in /var/www/mysite/data/www/mysite.io/core/Classes/Router.php on line 97

[Sun Jan 27 08:42:18.984905 2019] [fcgid:warn] [pid 28533] mod_fcgid: stderr: PHP Notice: Undefined offset: 1 in /var/www/mysite/data/www/mysite.io/core/Classes/Router.php on line 29, referer: mysite.io/en/

[Sun Jan 27 08:42:18.984922 2019] [fcgid:warn] [pid 28533] mod_fcgid: stderr: PHP Notice: Undefined offset: 1 in /var/www/mysite/data/www/mysite.io/core/Classes/Router.php on line 97, referer: mysite.io/en/

[Sun Jan 27 08:42:26.384808 2019] [fcgid:warn] [pid 28531] mod_fcgid: stderr: PHP Notice: Undefined offset: 1 in /var/www/mysite/data/www/mysite.io/core/Classes/Router.php on line 29, referer: mysite.io/ru/

[Sun Jan 27 08:42:26.384831 2019] [fcgid:warn] [pid 28531] mod_fcgid: stderr: PHP Notice: Undefined offset: 1 in /var/www/mysite/data/www/mysite.io/core/Classes/Router.php on line 97, referer: mysite.io/ru/

Файл Router.php

protected function prepare()
 {
    $url = trim($this->server->get(static::SERVER_KEY), '/');
    @list($root, $query) = explode('?', $url);

    list($lang, $requestUrl) = explode('/', $root, 2); //line 29

    if($this->server->is('POST')) {
        $requestUrl = $lang;
    } else {
        if(in_array($lang, [Lang::LANG_RU, Lang::LANG_EN]) && $lang == config('language.default')) {
            header('Location: /' . $requestUrl);
            die;
        }

        if(
            !in_array($lang, [Lang::LANG_RU, Lang::LANG_EN])
        ) {
            $requestUrl = $url;
            $lang = config('language.default');
        }

        if(
            in_array($lang, [Lang::LANG_RU, Lang::LANG_EN])
            && $lang != lang()->lang()
        ) {
            lang()->setLanguage($lang);

            if($lang == config('language.default')) {
                header('Location: /' . $requestUrl);
            } else {
                header('Location: /' . lang()->lang() . '/' . $requestUrl);
            }

            die;
        }
    }

    $this->url = $requestUrl;
    $this->full_url = $url;
    $this->query = $query;
    $this->params = $this->parseQuery($query);
    $this->arguments = $this->parseArguments($url);
}



protected function parseArguments($url)
 {
    $segments = explode('/', $url);

    $data = [];
    foreach ($segments as $segment) {
        if(in_array($segment, [Lang::LANG_RU, Lang::LANG_EN])) { //line 97
            continue;
        }

        $data[] = $segment;
    }
    return $data;
}

Файл Lang.php

protected function parseFromRaw($raw)
{
$lang = array_shift(explode(',', $raw)); //line 90

return in_array($lang, array_keys($this->getLanguagesList()))
    ? $lang
    : $this->defaultLanguage();
}