Remove array with key php

How to delete a specific element from an array in PHP

In this article, you will learn how to delete an element from an array using PHP. We will cover different methods to do it on different types of arrays with multiple examples.

Before going further, let’s cover how the three functions that we will need later work.

The unset() function

The unset() function is an in-built function in PHP used to unset/destroy a given variable or a set of variables.

Syntax

Parameters

The function requires at least one variable as the parameter, but you can pass multiple variables that you want to unset, separated with commas.

The unset() function has no return value.

After a variable is unset, the program behaves as if the variable never existed and no longer recognizes it. If you unset a variable then try to use it again in your program, the system gives the undefined variable error.

If the unset() function is called inside a user-defined function, it unsets only the local variables. If you want to unset a global variable inside the function (one that is initialized outside it), then you have to use the $GLOBALS array to do so.

The array_splice() function

The array_splice() function is in-built in PHP and removes the selected elements from an array and replaces them with new elements.

Syntax

array_splice(array1, start, length, array2)

Parameters

The array_values() function

The array_values() is an in-built PHP function that re-indexes an array and returns it with numeric keys, starting at 0 and increasing by 1.

Syntax

The array is a required parameter that specifies the array to be worked on.

How to delete an element from an array in PHP

Method 1: Using the unset() function

The unset() function can be used to destroy a whole array in a variable, or a specified element in the array using its index or key.

Unlike for the ordinary variables where we just pass the variable name to the function, to delete a specific element from the array and leave its other elements intact, we have to include the element index or key to the array variable when passing it to the unset() function.

Example 1

Deleting an element from a numerically indexed array based on its index.

"; print_r ($fruits); echo "
"; unset($fruits[1]); echo "The array after deleting an element 
"; print_r ($fruits); 

The array before deleting an element
Array ( [0] => Apple
[1] => Mango
[2] => Avocado
[3] => Banana
[4] => Watermelon
[5] => Passion
)
The array after deleting an element
Array ( [0] => Apple
[2] => Avocado
[3] => Banana
[4] => Watermelon
[5] => Passion
)

The array indices start from 0. So array element with an index of 1 is actually the second element in the array. We have passed the array name with index 1 to the unset() function. From the output, you can see the second element (Mango) has been deleted from the array.

One thing you can note from the above example is that after deleting the element with index 1, the function keeps the other indices untouched, ie index one is missing with the resulting array starting with index 0 followed by 2. The unset() function doesn’t re-index the array after deleting an element from a numerically indexed array.

To fix that and have the resulting array re-indexed, all you need to do is pass the array to the array_values() function.

Example 2

Re-indexing a numeric array using array_values() function after deleting an element with the unset() function.

The array before deleting an element
Array ( [0] => Apple
[1] => HP
[2] => Dell
[3] => Lenovo
)

As you can see from the output, we have deleted «Toshiba» which occupied index 2 of the array. After passing the array to the array_values() function, it has been re-indexed to have «Dell» shift from index 3 to 2 and «Lenovo» from index 4 to 3.

Example 3

Deleting an element from an associative array based on its key.

 "John Doe", "email" => "johndoe@gmail.com", "age" => 28); echo "The array before deleting an element 
"; print_r ($person); echo "
"; unset($person["age"]); echo "The array after deleting an element 
"; print_r ($person); 

The array before deleting an element
Array ( [name] => John Doe
[email] => johndoe@gmail.com
[age] => 28
)
The array after deleting an element
Array ( [name] => John Doe
[email] => johndoe@gmail.com
)

As you can see the age element has been deleted from the array.

If you know an array element value and don’t know its key/index but you want to delete it, you can do so y first using the array_search() function to get its key, then use that key to delete it.

You pass two parameters to the array_search() function where the first is the value whose key you want to know, and the second is the actual array from which you are searching the value. The function returns the key/index of the array element with that value.

The key for Watermelon is: 4

Example

"; print_r ($laptops); echo "
"; unset($laptops[array_search("Dell", $laptops)]); echo "The array after deleting an element 
"; print_r ($laptops); 

The array before deleting an element
Array ( [0] => Apple
[1] => HP
[2] => Toshiba
[3] => Dell
[4] => Lenovo
)
The array after deleting an element
Array ( [0] => Apple
[1] => HP
[2] => Toshiba
[4] => Lenovo
)

From the example above, we have used the array_search() function with value «Dell» to find the index of the array element that matches it, then used that index to delete the element using the unset() function. You can from the output it has worked because «Dell» was deleted from the array.

Method 2: Using the array_splice() function

This function removes a specified range of array elements and re-indexes the array numerically automatically.

As opposed to the unset() function, the array_splice() needs the offset as the second parameter and not an array key of the element in the array variable.

Example 1

"; print_r ($companies); echo "
"; array_splice($companies, 3, 1); echo "The array after deleting an element 
"; print_r ($companies); 

The array before deleting an element
Array ( [0] => SpaceX
[1] => Apple
[2] => Google
[3] => Tesla
[4] => Microsoft
)
The array after deleting an element
Array ( [0] => SpaceX
[1] => Apple
[2] => Google
[3] => Microsoft
)

The offset (start) parameter starts counting values from 0, the same way as array indices. To delete «Tesla», which is the fourth element, we had to use offset 3 and 1 for the length parameter since we only wanted to delete one element.

If for instance, we wanted to delete both Tesla and Microsoft, we would have used array_splice($companies, 3, 2) instead. 3 specifying the deletion to start from the fourth element, and 2 specifying the number of elements to be deleted.

As opposed to the unset() function which leaves the array indices untouched, you can see from the example above the array_splice() has re-indexed the array elements after the deletion.

Example 2

Deleting an element from an associative array using the array_splice() function.

 "John Doe", "email" => "johndoe@gmail.com", "age" => 28); echo "The array before deleting an element 
"; print_r ($person); echo "
"; array_splice($person, 1, 1); echo "The array after deleting an element 
"; print_r ($person); 

The array before deleting an element
Array ( [name] => John Doe
[email] => johndoe@gmail.com
[age] => 28
)
The array after deleting an element
Array ( [name] => John Doe
[age] => 28
)

The second element (email), whose offset is 1 has been deleted from the example above.

Now you know how to delete specific elements from arrays in PHP.

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How To Remove Specific Element From Array in PHP

Remove specific elements from array in PHP. In this tutorial, you will learn how to remove or delete specific elements from php array by key, value, and index in PHP.

How to Delete Specific Element From Array By Key, Value and Index in PHP

• Removing an array element by key
• Removing an array element by value
• Removing an array element by index
• Unset Multiple Keys from Array

Removing an array element by key

To remove an array element by key, you need to know the key of the element you want to remove.

 "red", "banana" => "yellow", "grape" => "purple"); unset($fruits["banana"]); print_r($fruits); ?>

In above-given code, you have an array of fruits with their colors. And you want to remove the element with the key “banana” from this array. Then you need to use the unset() function and pass in the key of the element to remove.

Removing an array element by value

To remove an array element by value, you need to search for the value and get its key. Then you can remove it from array by it’s value.

In the above-given code, you have same array, which you have used in first example. Then, you can use the array_search() function to search for the value and get its key. If the value is found, use the unset() function to remove the element with that key.

Removing an array element by index

To remove an array element by index, you need to know the index of the element, which you want to remove.

Unset Multiple Keys from Array

Sometimes, you may need to remove multiple elements from an array. So, you can use a loop to iterate through the array and call unset() on each key you want to remove.

$fruits = array( "apple" => 0.50, "banana" => 0.25, "cherry" => 1.00, "grape" => 0.75, "orange" => 0.30 ); $keys_to_remove = array("banana", "orange"); foreach ($keys_to_remove as $key) < if (array_key_exists($key, $fruits)) < unset($fruits[$key]); >>

• First, an associative array $fruits is created, which contains a list of fruits and their respective prices. Each fruit is a key-value pair, where the fruit name is the key, and the price is the value.
• Next, an array $keys_to_remove is defined, which contains the keys (i.e., fruit names) of the elements that you want to remove from the $fruits array.
• Then, a foreach loop is used to iterate through the $keys_to_remove array. On each iteration, the loop assigns the current element to the variable $key .
• Inside the loop, array_key_exists() the function is used to check if the current key exists in the $fruits array. This is important because if you try to unset a key that does not exist in the array, PHP will not raise an error, but will simply do nothing. Therefore, we need to ensure that the key exists before calling unset() .
• Finally, if the key exists in the $fruits array, the unset() the function is called to remove the element from the array. This effectively removes the element with the corresponding key from the $fruits array.

After running this code, the $fruits the array will look like this:

Array ( [apple] => 0.5 [cherry] => 1 [grape] => 0.75 )

Conclusion

The unset() a function is used to remove array elements by key, value, and index. By following the examples in this tutorial, you can learn how to manipulate arrays in your PHP applications effectively using unset() function. Remember that unset() removes the element from the array completely, and the remaining elements will be reindexed automatically.

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Author Admin

My name is Devendra Dode. I am a full-stack developer, entrepreneur, and owner of Tutsmake.com. I like writing tutorials and tips that can help other developers. I share tutorials of PHP, Python, Javascript, JQuery, Laravel, Livewire, Codeigniter, Node JS, Express JS, Vue JS, Angular JS, React Js, MySQL, MongoDB, REST APIs, Windows, Xampp, Linux, Ubuntu, Amazon AWS, Composer, SEO, WordPress, SSL and Bootstrap from a starting stage. As well as demo example.

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