Notice undefined index view in php

How to Solve PHP Notice: Undefined Index?

While working in PHP, you will come across two methods called $_POST and $_GET. These methods are used for obtaining values from the user through a form. When using them, you might encounter an error called “Notice: Undefined Index”.

This error means that within your code, there is a variable or constant that has no value assigned to it. But you may be trying to use the values obtained through the user form in your PHP code.

The error can be avoided by using the isset() function. This function will check whether the index variables are assigned a value or not, before using them.

Undefined Index PHP Error

An undefined index is a ‘notice’ such as the following:

“Notice: Undefined variable,”

“Notice: Undefined index” and “Notice: Undefined offset.”

As you can see above are all notices, here are two ways to deal with such notices.

1) Ignore such notices
2) Resolve such notices.

How to Ignore PHP Notice: Undefined Index

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

1. php.ini

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.

Change it to:

error_reporting = E_ALL & ~E_NOTICE

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

2. 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.

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

Solution or Fix for PHP Notice: Undefined Index

Cause of error:

This error occurs with $ _POST and $ _GET method when you use index or variables which have not set through $ _POST or $ _GET method, but you are already using their value in your PHP code.

Undefined index in PHP $_get

Example using $_GET

In the following example, we have used two variables ‘ names’ & ‘age,’ but we did set only the name variable through the $_GET method, that’s why it throws the notice.

http://yoursite.com/index.php?name=ram

Notice: Undefined index: age \index.php on line 5 

To solve such error, you can use the isset() function, which will check whether the index or variable is set or not, If not then don’t use it.

if(isset($_GET[index error name]))

Code with Error resolved using isset() function:

http://yoursite.com/index.php?name=ram

else < $name = "Name not set in GET Method"; >if(isset($_GET['age']))< $name = $_GET['age']; >else< $name = "
Age not set in GET Method"; > echo $name; echo $age; ?> 

ram Age not set in GET Method 

Set Index as blank

We can also set the index as blank index:

// example with $_POST method $name = isset($_POST['name']) ? $_POST['name'] : ''; $name = isset($_POST['age']) ? $_POST['age'] : ''; // example with $_GET method $name = isset($_GET['name']) ? $_GET['name'] : ''; $name = isset($_GET['age']) ? $_GET['age'] : ''; 

Notice: Undefined Variable

This notice occurs when you use any variable in your PHP code, which is not set.

Notice: Undefined variable: age in D:\xampp\htdocs\testsite.loc\index.php on line 7 

In the above example, we are displaying value stored in the ‘name’ and ‘age’ variable, but we didn’t set the ‘age’ variable.

To fix this type of error, you can define the variable as global and use the isset() function to check if this set or not.

Notice: Undefined Offset

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.”

'Red',3=>'Green',4=>'Blue',5=>'Yellow'); // echo value of array at offset 1. echo $colorarray[1]; ?> 

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

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

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

• Learn PHP Language
• PHP Interview Questions and Answers
• PHP Training Tutorials for Beginners
• Display Pdf/Word Document in Browser Using PHP
• Call PHP Function from JavaScript
• Call a JavaScript Function from PHP
• PHP Pagination
• Alert Box in PHP
• Php Count Function
• PHP Filter_var ()
• PHP array_push Function
• strpos in PHP
• PHP in_array Function
• PHP strtotime() function
• PHP array_merge() Function
• explode() in PHP
• implode() in PHP
• PHP array_map()

Источник

PHP Notice Undefined Index

Notice Undefined Index in PHP is an error which occurs when we try to access the value or variable which does not even exist in reality. Undefined Index is the usual error that comes up when we try to access the variable which does not persist. For instance, an array we are trying to access the index does not really exist in that, so in this scenario, we will get an Undefined Index in PHP. Undefined here means we have not defined its value and trying to access it.

Web development, programming languages, Software testing & others

Syntax of PHP Notice Undefined Index

There is no such syntax defined for an undefined index in php because it a kind of error we get when we try to access the value or variable in our code that does not really exist or no value assign to them, and we are trying to access its value somewhere in the code.

$myarray = array(value1, value2, value3, so on..) $myarray[value_does_not_exists]

In the above lines of syntax, we are trying to access the array by passing a key which does not exist in the array. So this will throw us an Undefined index error in runtime.

Let’s see one example of how we can do this while programming:

$myarray = array(100, 200, 300, 400) $myarray[1000]

In this way, we can replicate this error in PHP, but this can be prevented by using isst() method in PHP to make our code working in such a situation.

How does Notice Undefined Index work in PHP?

As of now, we know that an undefined index is a kind of exception, or we can say error in PHP. This will occur if we want to access a variable that does not really exist in our program. This needs to be handled; otherwise, it will cause a serious issue to our application and termination of the program. We have some methods defined in PHP to handle this kind of error in a program.

Here we will see one sample piece of code and its working, how this occurs in the program and how it should be handle.

In the above code lines, we create one array named ‘$myarray’, and we have initialized its value with some string integers inside it. In the second line, we are trying to access the variable of the array by using the value assigned to it and also, we are using the index. So index ‘4’ is present in the array, so this line would work fine as expected, but immediately after this line, we have another line in which we are trying to access the array element by its key. So, in this case, we will get Notice: Undefined Index in PHP with line number mentioned in it. We will now see how we can prevent this from happening in our code; for this, we have two methods available in PHP that can be used before accessing the element or value from the array.

Given below are the methods:

1. array_key_exists()

This method is used to check whether the key is present inside the array or not before access its value. This method can be used where we are trying to access the array element, and we are not sure about this. So before using the variable’s value, we can check by using this method whether the element or key exists.

This method takes two parameters as the input parameter. The first line is the key and the second one is an array itself.

Let’s see its syntax of the method

array_key_exists(your_key, your_array)

Here we pass two parameters the key we pass it checks it into the whole array. Its return type is Boolean; it will return true if the key is present in the array, else it will return false if the keys does not exist.

2. isset()

This method also checks variable is set in the program or not before accessing its value. It also checks for a NULL variable. It performs two things it; first checks variable is defined, and the other is it should not be NULL.

Here we can pass our variable, which we want to check before accessing them in the program. The return type for this method is also Boolean; if it found the variable and it is not NULL, then it will return as true as the value. If the previous condition not specified, then it will return False.

Examples of PHP Notice Undefined Index

Given below are the examples of PHP Notice Undefined Index:

Example #1

In this example, we are trying to access the key that does not access the array, so while program execution, we will get Notice Undefined Index error in PHP.

'Hi',1=>'Hello',2=>'To', 3=>'All', 4=>'Stay', 5=>'Safe', 6=>'Enjoy !!'); //try to print values from array echo $myarray[0]."\n"; echo $myarray[1]."\n"; echo $myarray[2]."\n"; //trying to access the element which does not exists. echo $myarray['World']."\n"; ?>

Example #2

To prevent this error while occurring in program execution.

'Hi',1=>'Hello',2=>'To', 3=>'All', 4=>'Stay', 5=>'Safe', 6=>'Enjoy !!'); //try to print values from array echo $myarray[0]."\n"; echo $myarray[1]."\n"; echo $myarray[2]."\n"; //trying to access the element which does not exists. if(array_key_exists('World', $myarray))< echo "Key exists in array !!"; >else < echo "Key does not exists in array !! :)"; >?>

Conclusion

Notice Undefined Index is a kind of error we got in PHP when we try to access the non-existing element from the array or in our program. One more case is that it can occur when we try to access a NULL value in the program. So we can use two methods, isset() and array_key_exists() methods in PHP, to overcome this error in the application.

Recommended Articles

This is a guide to PHP Notice Undefined Index. Here we discuss the introduction, syntax, and working of notice undefined index in PHP along with different examples. You may also have a look at the following articles to learn more –

25+ Hours of HD Videos
5 Courses
6 Mock Tests & Quizzes
Verifiable Certificate of Completion
Lifetime Access
4.5

92+ Hours of HD Videos
22 Courses
2 Mock Tests & Quizzes
Verifiable Certificate of Completion
Lifetime Access
4.5

83+ Hours of HD Videos
16 Courses
1 Mock Tests & Quizzes
Verifiable Certificate of Completion
Lifetime Access
4.5

PHP Course Bundle — 8 Courses in 1 | 3 Mock Tests
43+ Hours of HD Videos
8 Courses
3 Mock Tests & Quizzes
Verifiable Certificate of Completion
Lifetime Access
4.5

Источник