Use unset to delete the key Street:
<?php
$arr1 = array("Name" => "Johm", "Street" => "Waall", "Country" => "India");
unset($arr1["Street"]);
?>
RESULT:
array("Name" => "Johm","Country" => "India")`
This will not re-index the array after deleting the value, so use array_splice();
Suppose you have the following array:
Array
(
[user_id] => 193
[storage] => 5
)
To delete storage, do:
unset($attributes['storage']);
$attributes = array_filter($attributes);
And you get:
Array
(
[user_id] => 193
)
Use array_search to get the key and remove it with unset if found:
if (($key = array_search('word', $array)) !== false) {
unset($array[$key]);
}
There are two methods to do this task: unset() and array_splice()
Let us assume two arrays:
$array_1 = array('a'=>'One', 'b'=>'Two', 'c'=>'Three');
$array_2 = array('Red', 'Yellow', 'White', 'Black', 'Green');
With unset()
syntax - unset(array_element)
unset($array_1['a']); // Any valid key
unset($array_2[0]); // Any valid index
With array_splice()
syntax - array_splice(array, index, length)
array_splice($array_1, 1, 1); // Remove one element from $array_1 from index 1
array_splice($array_2, 3, 1); // Remove one element from $array_2 from index 3
<?php
$array = array("your array");
$array = array_diff($array, ["element you want to delete"]);
?>
Create your array in the variable $array and then where I have put 'element you want to delete' you put something like: "a". And if you want to delete multiple items then: "a", "b".
I came here because I wanted to see if there was a more elegant solution to this problem than using unset($arr[$i]). To my disappointment these answers are either wrong or do not cover every edge case.
Here is why array_diff() does not work. Keys are unique in the array, while elements are not always unique.
$arr = [1,2,2,3];
foreach($arr as $i => $n){
$b = array_diff($arr,[$n]);
echo "\n".json_encode($b);
}
Results...
[2,2,3]
[1,3]
[1,2,2]
If two elements are the same they will be remove. This also applies for array_search() and array_flip().
I saw a lot of answers with array_slice() and array_splice(), but these functions only work with numeric arrays. All the answers I am aware if here does not answer the question, and so here is a solution that will work.
$arr = [1,2,3];
foreach($arr as $i => $n){
$b = array_merge(array_slice($arr,0,$i),array_slice($arr,$i+1));
echo "\n".json_encode($b);
}
Results...
[2,3];
[1,3];
[1,2];
Since unset($arr[$i]) will work on both associative array and numeric arrays this still does not answer the question.
This solution is to compare the keys and with a tool that will handle both numeric and associative arrays. I use array_diff_uassoc() for this. This function compares the keys in a call back function.
$arr = [1,2,2,3];
//$arr = ['a'=>'z','b'=>'y','c'=>'x','d'=>'w'];
foreach($arr as $key => $n){
$b = array_diff_uassoc($arr, [$key=>$n], function($a,$b) {
if($a != $b){
return 1;
}
});
echo "\n".json_encode($b);
}
Results.....
[2,2,3];
[1,2,3];
[1,2,2];
['b'=>'y','c'=>'x','d'=>'w'];
['a'=>'z','c'=>'x','d'=>'w'];
['a'=>'z','b'=>'y','d'=>'w'];
['a'=>'z','b'=>'y','c'=>'x'];
unset doesn't change the index, but array_splice does:
$arrayName = array('1' => 'somevalue',
'2' => 'somevalue1',
'3' => 'somevalue3',
500 => 'somevalue500',
);
echo $arrayName['500'];
//somevalue500
array_splice($arrayName, 1, 2);
print_r($arrayName);
//Array ( [0] => somevalue [1] => somevalue500 )
$arrayName = array( '1' => 'somevalue',
'2' => 'somevalue1',
'3' => 'somevalue3',
500 => 'somevalue500',
);
echo $arrayName['500'];
//somevalue500
unset($arrayName[1]);
print_r($arrayName);
//Array ( [0] => somevalue [1] => somevalue500 )
For associative arrays, use unset:
$arr = array('a' => 1, 'b' => 2, 'c' => 3);
unset($arr['b']);
// RESULT: array('a' => 1, 'c' => 3)
For numeric arrays, use array_splice:
$arr = array(1, 2, 3);
array_splice($arr, 1, 1);
// RESULT: array(0 => 1, 1 => 3)
Using unset for numeric arrays will not produce an error, but it will mess up your indexes:
$arr = array(1, 2, 3);
unset($arr[1]);
// RESULT: array(0 => 1, 2 => 3)
For associative arrays, with non-integer keys:
Simply, unset($array[$key]) would work.
For arrays having integer keys and if you want to maintain your keys:
$array = [ 'mango', 'red', 'orange', 'grapes'];
unset($array[2]);
$array = array_values($array);
array_splice($array, 2, 1);
$arrayName = array( '1' => 'somevalue',
'2' => 'somevalue1',
'3' => 'somevalue3',
);
print_r($arrayName[1]);
// somevalue
unset($arrayName[1]);
print_r($arrayName);
Destroy a single element of an array
unset()
$array1 = array('A', 'B', 'C', 'D', 'E');
unset($array1[2]); // Delete known index(2) value from array
var_dump($array1);
The output will be:
array(4) {
[0]=>
string(1) "A"
[1]=>
string(1) "B"
[3]=>
string(1) "D"
[4]=>
string(1) "E"
}
If you need to re index the array:
$array1 = array_values($array1);
var_dump($array1);
Then the output will be:
array(4) {
[0]=>
string(1) "A"
[1]=>
string(1) "B"
[2]=>
string(1) "D"
[3]=>
string(1) "E"
}
Pop the element off the end of array - return the value of the removed element
mixed array_pop(array &$array)
$stack = array("orange", "banana", "apple", "raspberry");
$last_fruit = array_pop($stack);
print_r($stack);
print_r('Last Fruit:'.$last_fruit); // Last element of the array
The output will be
Array
(
[0] => orange
[1] => banana
[2] => apple
)
Last Fruit: raspberry
Remove the first element (red) from an array, - return the value of the removed element
mixed array_shift ( array &$array )
$color = array("a" => "red", "b" => "green" , "c" => "blue");
$first_color = array_shift($color);
print_r ($color);
print_r ('First Color: '.$first_color);
The output will be:
Array
(
[b] => green
[c] => blue
)
First Color: red
unset($array[$index]);
Use the following code:
$arr = array('orange', 'banana', 'apple', 'raspberry');
$result = array_pop($arr);
print_r($result);
It should be noted that unset() will keep indexes untouched, which is what you'd expect when using string indexes (array as hashtable), but can be quite surprising when dealing with integer indexed arrays:
$array = array(0, 1, 2, 3);
unset($array[2]);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[3]=>
int(3)
} */
$array = array(0, 1, 2, 3);
array_splice($array, 2, 1);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(3)
} */
So array_splice() can be used if you'd like to normalize your integer keys. Another option is using array_values() after unset():
$array = array(0, 1, 2, 3);
unset($array[2]);
$array = array_values($array);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(3)
} */
Follow the default functions:
unset() destroys the specified variables. For more info, you can refer to PHP unset
$Array = array("test1", "test2", "test3", "test3");
unset($Array[2]);
The array_pop() function deletes the last element of an array. For more info, you can refer to PHP array_pop
$Array = array("test1", "test2", "test3", "test3");
array_pop($Array);
The array_splice() function removes selected elements from an array and replaces it with new elements. For more info, you can refer to PHP array_splice
$Array = array("test1", "test2", "test3", "test3");
array_splice($Array,1,2);
The array_shift() function removes the first element from an array. For more info, you can refer to PHP array_shift
$Array = array("test1", "test2", "test3", "test3");
array_shift($Array);
While unset() has been mentioned here several times, it has yet to be mentioned that unset() accepts multiple variables making it easy to delete multiple, noncontiguous elements from an array in one operation:
// Delete multiple, noncontiguous elements from an array
$array = [ 'foo', 'bar', 'baz', 'quz' ];
unset( $array[2], $array[3] );
print_r($array);
// Output: [ 'foo', 'bar' ]
unset() does not accept an array of keys to remove, so the code below will fail (it would have made it slightly easier to use unset() dynamically though).
$array = range(0,5);
$remove = [1,2];
$array = unset( $remove ); // FAILS: "unexpected 'unset'"
print_r($array);
Instead, unset() can be used dynamically in a foreach loop:
$array = range(0,5);
$remove = [1,2];
foreach ($remove as $k=>$v) {
unset($array[$v]);
}
print_r($array);
// Output: [ 0, 3, 4, 5 ]
There is also another practice that has yet to be mentioned. Sometimes, the simplest way to get rid of certain array keys is to simply copy $array1 into $array2.
$array1 = range(1,10);
foreach ($array1 as $v) {
// Remove all even integers from the array
if( $v % 2 ) {
$array2[] = $v;
}
}
print_r($array2);
// Output: [ 1, 3, 5, 7, 9 ];
Obviously, the same practice applies to text strings:
$array1 = [ 'foo', '_bar', 'baz' ];
foreach ($array1 as $v) {
// Remove all strings beginning with underscore
if( strpos($v,'_')===false ) {
$array2[] = $v;
}
}
print_r($array2);
// Output: [ 'foo', 'baz' ]
Use the unset function like below:
$a = array(
'salam',
'10',
1
);
unset($a[1]);
print_r($a);
/*
Output:
Array
(
[0] => salam
[2] => 1
)
*/
Use the array_search function to get an element key and use the above manner to remove an array element like below:
$a = array(
'salam',
'10',
1
);
$key = array_search(10, $a);
if ($key !== false) {
unset($a[$key]);
}
print_r($a);
/*
Output:
Array
(
[0] => salam
[2] => 1
)
*/
You can use the array_pop method to remove the last element of an array:
<?php
$a = array("one", "two", "Three");
array_pop($a);
print_r($a);
?>
The out put will be
Array ( [0] => one[1] => two)
which deletes only last element of an array LIFO operation
if you want to remove a specific object of an array by reference of that object you can do following:
unset($array[array_search($object,$array)]);
Example:
<?php
class Foo
{
public $id;
public $name;
}
$foo1 = new Foo();
$foo1->id = 1;
$foo1->name = 'Name1';
$foo2 = new Foo();
$foo2->id = 2;
$foo2->name = 'Name2';
$foo3 = new Foo();
$foo3->id = 3;
$foo3->name = 'Name3';
$array = array($foo1,$foo2,$foo3);
unset($array[array_search($foo2,$array)]);
echo '<pre>';
var_dump($array);
echo '</pre>';
?>
Result:
array(2) {
[0]=>
object(Foo)#1 (2) {
["id"]=>
int(1)
["name"]=>
string(5) "Name1"
}
[2]=>
object(Foo)#3 (2) {
["id"]=>
int(3)
["name"]=>
string(5) "Name3"
}
}
Note that if the object occures several times it will only be removed the first occurence!
You can simply use unset() to delete an array.
Remember that an array must be unset after the foreach function.
// Our initial array
$arr = array("blue", "green", "red", "yellow", "green", "orange", "yellow", "indigo", "red");
print_r($arr);
// Remove the elements who's values are yellow or red
$arr = array_diff($arr, array("yellow", "red"));
print_r($arr);
This is the output from the code above:
Array
(
[0] => blue
[1] => green
[2] => red
[3] => yellow
[4] => green
[5] => orange
[6] => yellow
[7] => indigo
[8] => red
)
Array
(
[0] => blue
[1] => green
[4] => green
[5] => orange
[7] => indigo
)
Now, array_values() will reindex a numerical array nicely, but it will remove all key strings from the array and replace them with numbers. If you need to preserve the key names (strings), or reindex the array if all keys are numerical, use array_merge():
$arr = array_merge(array_diff($arr, array("yellow", "red")));
print_r($arr);
Outputs
Array
(
[0] => blue
[1] => green
[2] => green
[3] => orange
[4] => indigo
)
Use array_search to get the key and remove it with unset if found:
if (($key = array_search('word', $array)) !== false) {
unset($array[$key]);
}
// Remove by value
function removeFromArr($arr, $val)
{
unset($arr[array_search($val, $arr)]);
return array_values($arr);
}
unset($array[$index]);
$key = array_search($needle, $array);
if ($key !== false) {
unset($array[$key]);
}
If the index is specified:
$arr = ['a', 'b', 'c'];
$index = 0;
unset($arr[$index]); // $arr = ['b', 'c']
If the index is NOT specified:
$arr = ['a', 'b', 'c'];
$index = array_search('a', $arr); // search the value to find index
if($index !== false){
unset($arr[$index]); // $arr = ['b', 'c']
}
The if condition is necessary
because if index is not found, unset() will automatically delete
the first element of the array which is not what we want.
To avoid doing a search one can play around with array_diff:
$array = array(3, 9, 11, 20);
$array = array_diff($array, array(11) ); // removes 11
In this case one doesn't have to search/use the key.
You can use the array_pop method to remove the last element of an array:
<?php
$a = array("one", "two", "Three");
array_pop($a);
print_r($a);
?>
The out put will be
Array ( [0] => one[1] => two)
which deletes only last element of an array LIFO operation
There are two methods to do this task: unset() and array_splice()
Let us assume two arrays:
$array_1 = array('a'=>'One', 'b'=>'Two', 'c'=>'Three');
$array_2 = array('Red', 'Yellow', 'White', 'Black', 'Green');
With unset()
syntax - unset(array_element)
unset($array_1['a']); // Any valid key
unset($array_2[0]); // Any valid index
With array_splice()
syntax - array_splice(array, index, length)
array_splice($array_1, 1, 1); // Remove one element from $array_1 from index 1
array_splice($array_2, 3, 1); // Remove one element from $array_2 from index 3
<?php
$array = array("your array");
$array = array_diff($array, ["element you want to delete"]);
?>
Create your array in the variable $array and then where I have put 'element you want to delete' you put something like: "a". And if you want to delete multiple items then: "a", "b".
For those of you who are looking for Ruby's hash#delete equivalent in PHP:
<?php
function array_delete(&$array, $key) {
if (!isset($array[$key])) {
return null;
}
$value = $array[$key];
unset($array[$key]);
return $value;
}
This will not only delete the element from your array, but it will also return the value stored in that key so you can consume your array in a non-linear fashion.
unset doesn't change the index, but array_splice does:
$arrayName = array('1' => 'somevalue',
'2' => 'somevalue1',
'3' => 'somevalue3',
500 => 'somevalue500',
);
echo $arrayName['500'];
//somevalue500
array_splice($arrayName, 1, 2);
print_r($arrayName);
//Array ( [0] => somevalue [1] => somevalue500 )
$arrayName = array( '1' => 'somevalue',
'2' => 'somevalue1',
'3' => 'somevalue3',
500 => 'somevalue500',
);
echo $arrayName['500'];
//somevalue500
unset($arrayName[1]);
print_r($arrayName);
//Array ( [0] => somevalue [1] => somevalue500 )
I'd just like to say I had a particular object that had variable attributes (it was basically mapping a table and I was changing the columns in the table, so the attributes in the object, reflecting the table would vary as well):
class obj {
protected $fields = array('field1','field2');
protected $field1 = array();
protected $field2 = array();
protected loadfields(){}
// This will load the $field1 and $field2 with rows of data for the column they describe
protected function clearFields($num){
foreach($fields as $field) {
unset($this->$field[$num]);
// This did not work the line below worked
unset($this->{$field}[$num]); // You have to resolve $field first using {}
}
}
}
The whole purpose of $fields was just, so I don't have to look everywhere in the code when they're changed, I just look at the beginning of the class and change the list of attributes and the $fields array content to reflect the new attributes.
<?php
$stack = ["fruit1", "fruit2", "fruit3", "fruit4"];
$fruit = array_shift($stack);
print_r($stack);
echo $fruit;
?>
Output:
[
[0] => fruit2
[1] => fruit3
[2] => fruit4
]
fruit1
This may help...
<?php
$a1 = array("a"=>"red", "b"=>"green", "c"=>"blue", "d"=>"yellow");
$a2 = array("a"=>"purple", "b"=>"orange");
array_splice($a1, 0, 2, $a2);
print_r($a1);
?>
The result will be:
Array ( [0] => purple [1] => orange [c] => blue [d] => yellow )
You can simply use unset() to delete an array.
Remember that an array must be unset after the foreach function.
If you have a numerically indexed array where all values are unique (or they are non-unique but you wish to remove all instances of a particular value), you can simply use array_diff() to remove a matching element, like this:
$my_array = array_diff($my_array, array('Value_to_remove'));
For example:
$my_array = array('Andy', 'Bertha', 'Charles', 'Diana');
echo sizeof($my_array) . "\n";
$my_array = array_diff($my_array, array('Charles'));
echo sizeof($my_array);
This displays the following:
4
3
In this example, the element with the value 'Charles' is removed as can be verified by the sizeof() calls that report a size of 4 for the initial array, and 3 after the removal.
If you need to remove multiple elements from an associative array, you can use array_diff_key() (here used with array_flip()):
$my_array = array(
"key1" => "value 1",
"key2" => "value 2",
"key3" => "value 3",
"key4" => "value 4",
"key5" => "value 5",
);
$to_remove = array("key2", "key4");
$result = array_diff_key($my_array, array_flip($to_remove));
print_r($result);
Output:
Array ( [key1] => value 1 [key3] => value 3 [key5] => value 5 )
$x = array(1, 2, 3, 4, 5);
var_dump($x);
unset($x[3]); // Here is the key to be deleted
echo '<br>';
array_values($x);
var_dump($x);
For associative arrays, with non-integer keys:
Simply, unset($array[$key]) would work.
For arrays having integer keys and if you want to maintain your keys:
$array = [ 'mango', 'red', 'orange', 'grapes'];
unset($array[2]);
$array = array_values($array);
array_splice($array, 2, 1);
unset() destroys the specified variables.
The behavior of unset() inside of a function can vary depending on what type of variable you are attempting to destroy.
If a globalized variable is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset() was called.
<?php
function destroy_foo()
{
global $foo;
unset($foo);
}
$foo = 'bar';
destroy_foo();
echo $foo;
?>
The answer of the above code will be bar.
To unset() a global variable inside of a function:
<?php
function foo()
{
unset($GLOBALS['bar']);
}
$bar = "something";
foo();
?>
$key = array_search($needle, $array);
if ($key !== false) {
unset($array[$key]);
}
Use the unset function like below:
$a = array(
'salam',
'10',
1
);
unset($a[1]);
print_r($a);
/*
Output:
Array
(
[0] => salam
[2] => 1
)
*/
Use the array_search function to get an element key and use the above manner to remove an array element like below:
$a = array(
'salam',
'10',
1
);
$key = array_search(10, $a);
if ($key !== false) {
unset($a[$key]);
}
print_r($a);
/*
Output:
Array
(
[0] => salam
[2] => 1
)
*/
// Our initial array
$arr = array("blue", "green", "red", "yellow", "green", "orange", "yellow", "indigo", "red");
print_r($arr);
// Remove the elements who's values are yellow or red
$arr = array_diff($arr, array("yellow", "red"));
print_r($arr);
This is the output from the code above:
Array
(
[0] => blue
[1] => green
[2] => red
[3] => yellow
[4] => green
[5] => orange
[6] => yellow
[7] => indigo
[8] => red
)
Array
(
[0] => blue
[1] => green
[4] => green
[5] => orange
[7] => indigo
)
Now, array_values() will reindex a numerical array nicely, but it will remove all key strings from the array and replace them with numbers. If you need to preserve the key names (strings), or reindex the array if all keys are numerical, use array_merge():
$arr = array_merge(array_diff($arr, array("yellow", "red")));
print_r($arr);
Outputs
Array
(
[0] => blue
[1] => green
[2] => green
[3] => orange
[4] => indigo
)
<?php
// If you want to remove a particular array element use this method
$my_array = array("key1"=>"value 1", "key2"=>"value 2", "key3"=>"value 3");
print_r($my_array);
if (array_key_exists("key1", $my_array)) {
unset($my_array['key1']);
print_r($my_array);
}
else {
echo "Key does not exist";
}
?>
<?php
//To remove first array element
$my_array = array("key1"=>"value 1", "key2"=>"value 2", "key3"=>"value 3");
print_r($my_array);
$new_array = array_slice($my_array, 1);
print_r($new_array);
?>
<?php
echo "<br/> ";
// To remove first array element to length
// starts from first and remove two element
$my_array = array("key1"=>"value 1", "key2"=>"value 2", "key3"=>"value 3");
print_r($my_array);
$new_array = array_slice($my_array, 1, 2);
print_r($new_array);
?>
Output
Array ( [key1] => value 1 [key2] => value 2 [key3] =>
value 3 ) Array ( [key2] => value 2 [key3] => value 3 )
Array ( [key1] => value 1 [key2] => value 2 [key3] => value 3 )
Array ( [key2] => value 2 [key3] => value 3 )
Array ( [key1] => value 1 [key2] => value 2 [key3] => value 3 )
Array ( [key2] => value 2 [key3] => value 3 )
To avoid doing a search one can play around with array_diff:
$array = array(3, 9, 11, 20);
$array = array_diff($array, array(11) ); // removes 11
In this case one doesn't have to search/use the key.
I came here because I wanted to see if there was a more elegant solution to this problem than using unset($arr[$i]). To my disappointment these answers are either wrong or do not cover every edge case.
Here is why array_diff() does not work. Keys are unique in the array, while elements are not always unique.
$arr = [1,2,2,3];
foreach($arr as $i => $n){
$b = array_diff($arr,[$n]);
echo "\n".json_encode($b);
}
Results...
[2,2,3]
[1,3]
[1,2,2]
If two elements are the same they will be remove. This also applies for array_search() and array_flip().
I saw a lot of answers with array_slice() and array_splice(), but these functions only work with numeric arrays. All the answers I am aware if here does not answer the question, and so here is a solution that will work.
$arr = [1,2,3];
foreach($arr as $i => $n){
$b = array_merge(array_slice($arr,0,$i),array_slice($arr,$i+1));
echo "\n".json_encode($b);
}
Results...
[2,3];
[1,3];
[1,2];
Since unset($arr[$i]) will work on both associative array and numeric arrays this still does not answer the question.
This solution is to compare the keys and with a tool that will handle both numeric and associative arrays. I use array_diff_uassoc() for this. This function compares the keys in a call back function.
$arr = [1,2,2,3];
//$arr = ['a'=>'z','b'=>'y','c'=>'x','d'=>'w'];
foreach($arr as $key => $n){
$b = array_diff_uassoc($arr, [$key=>$n], function($a,$b) {
if($a != $b){
return 1;
}
});
echo "\n".json_encode($b);
}
Results.....
[2,2,3];
[1,2,3];
[1,2,2];
['b'=>'y','c'=>'x','d'=>'w'];
['a'=>'z','c'=>'x','d'=>'w'];
['a'=>'z','b'=>'y','d'=>'w'];
['a'=>'z','b'=>'y','c'=>'x'];
$arrayName = array( '1' => 'somevalue',
'2' => 'somevalue1',
'3' => 'somevalue3',
);
print_r($arrayName[1]);
// somevalue
unset($arrayName[1]);
print_r($arrayName);
if you want to remove a specific object of an array by reference of that object you can do following:
unset($array[array_search($object,$array)]);
Example:
<?php
class Foo
{
public $id;
public $name;
}
$foo1 = new Foo();
$foo1->id = 1;
$foo1->name = 'Name1';
$foo2 = new Foo();
$foo2->id = 2;
$foo2->name = 'Name2';
$foo3 = new Foo();
$foo3->id = 3;
$foo3->name = 'Name3';
$array = array($foo1,$foo2,$foo3);
unset($array[array_search($foo2,$array)]);
echo '<pre>';
var_dump($array);
echo '</pre>';
?>
Result:
array(2) {
[0]=>
object(Foo)#1 (2) {
["id"]=>
int(1)
["name"]=>
string(5) "Name1"
}
[2]=>
object(Foo)#3 (2) {
["id"]=>
int(3)
["name"]=>
string(5) "Name3"
}
}
Note that if the object occures several times it will only be removed the first occurence!
<?php
// If you want to remove a particular array element use this method
$my_array = array("key1"=>"value 1", "key2"=>"value 2", "key3"=>"value 3");
print_r($my_array);
if (array_key_exists("key1", $my_array)) {
unset($my_array['key1']);
print_r($my_array);
}
else {
echo "Key does not exist";
}
?>
<?php
//To remove first array element
$my_array = array("key1"=>"value 1", "key2"=>"value 2", "key3"=>"value 3");
print_r($my_array);
$new_array = array_slice($my_array, 1);
print_r($new_array);
?>
<?php
echo "<br/> ";
// To remove first array element to length
// starts from first and remove two element
$my_array = array("key1"=>"value 1", "key2"=>"value 2", "key3"=>"value 3");
print_r($my_array);
$new_array = array_slice($my_array, 1, 2);
print_r($new_array);
?>
Output
Array ( [key1] => value 1 [key2] => value 2 [key3] =>
value 3 ) Array ( [key2] => value 2 [key3] => value 3 )
Array ( [key1] => value 1 [key2] => value 2 [key3] => value 3 )
Array ( [key2] => value 2 [key3] => value 3 )
Array ( [key1] => value 1 [key2] => value 2 [key3] => value 3 )
Array ( [key2] => value 2 [key3] => value 3 )
Use unset to delete the key Street:
<?php
$arr1 = array("Name" => "Johm", "Street" => "Waall", "Country" => "India");
unset($arr1["Street"]);
?>
RESULT:
array("Name" => "Johm","Country" => "India")`
This will not re-index the array after deleting the value, so use array_splice();
Suppose you have the following array:
Array
(
[user_id] => 193
[storage] => 5
)
To delete storage, do:
unset($attributes['storage']);
$attributes = array_filter($attributes);
And you get:
Array
(
[user_id] => 193
)
<?php
$stack = ["fruit1", "fruit2", "fruit3", "fruit4"];
$fruit = array_shift($stack);
print_r($stack);
echo $fruit;
?>
Output:
[
[0] => fruit2
[1] => fruit3
[2] => fruit4
]
fruit1
Two ways for removing the first item of an array with keeping order of the index and also if you don't know the key name of the first item.
// 1 is the index of the first object to get
// NULL to get everything until the end
// true to preserve keys
$array = array_slice($array, 1, null, true);
// Rewinds the array's internal pointer to the first element
// and returns the value of the first array element.
$value = reset($array);
// Returns the index element of the current array position
$key = key($array);
unset($array[$key]);
For this sample data:
$array = array(10 => "a", 20 => "b", 30 => "c");
You must have this result:
array(2) {
[20]=>
string(1) "b"
[30]=>
string(1) "c"
}
If you need to remove multiple elements from an associative array, you can use array_diff_key() (here used with array_flip()):
$my_array = array(
"key1" => "value 1",
"key2" => "value 2",
"key3" => "value 3",
"key4" => "value 4",
"key5" => "value 5",
);
$to_remove = array("key2", "key4");
$result = array_diff_key($my_array, array_flip($to_remove));
print_r($result);
Output:
Array ( [key1] => value 1 [key3] => value 3 [key5] => value 5 )
While unset() has been mentioned here several times, it has yet to be mentioned that unset() accepts multiple variables making it easy to delete multiple, noncontiguous elements from an array in one operation:
// Delete multiple, noncontiguous elements from an array
$array = [ 'foo', 'bar', 'baz', 'quz' ];
unset( $array[2], $array[3] );
print_r($array);
// Output: [ 'foo', 'bar' ]
unset() does not accept an array of keys to remove, so the code below will fail (it would have made it slightly easier to use unset() dynamically though).
$array = range(0,5);
$remove = [1,2];
$array = unset( $remove ); // FAILS: "unexpected 'unset'"
print_r($array);
Instead, unset() can be used dynamically in a foreach loop:
$array = range(0,5);
$remove = [1,2];
foreach ($remove as $k=>$v) {
unset($array[$v]);
}
print_r($array);
// Output: [ 0, 3, 4, 5 ]
There is also another practice that has yet to be mentioned. Sometimes, the simplest way to get rid of certain array keys is to simply copy $array1 into $array2.
$array1 = range(1,10);
foreach ($array1 as $v) {
// Remove all even integers from the array
if( $v % 2 ) {
$array2[] = $v;
}
}
print_r($array2);
// Output: [ 1, 3, 5, 7, 9 ];
Obviously, the same practice applies to text strings:
$array1 = [ 'foo', '_bar', 'baz' ];
foreach ($array1 as $v) {
// Remove all strings beginning with underscore
if( strpos($v,'_')===false ) {
$array2[] = $v;
}
}
print_r($array2);
// Output: [ 'foo', 'baz' ]
This may help...
<?php
$a1 = array("a"=>"red", "b"=>"green", "c"=>"blue", "d"=>"yellow");
$a2 = array("a"=>"purple", "b"=>"orange");
array_splice($a1, 0, 2, $a2);
print_r($a1);
?>
The result will be:
Array ( [0] => purple [1] => orange [c] => blue [d] => yellow )
Also, for a named element:
unset($array["elementName"]);
I'd just like to say I had a particular object that had variable attributes (it was basically mapping a table and I was changing the columns in the table, so the attributes in the object, reflecting the table would vary as well):
class obj {
protected $fields = array('field1','field2');
protected $field1 = array();
protected $field2 = array();
protected loadfields(){}
// This will load the $field1 and $field2 with rows of data for the column they describe
protected function clearFields($num){
foreach($fields as $field) {
unset($this->$field[$num]);
// This did not work the line below worked
unset($this->{$field}[$num]); // You have to resolve $field first using {}
}
}
}
The whole purpose of $fields was just, so I don't have to look everywhere in the code when they're changed, I just look at the beginning of the class and change the list of attributes and the $fields array content to reflect the new attributes.
Follow the default functions:
unset() destroys the specified variables. For more info, you can refer to PHP unset
$Array = array("test1", "test2", "test3", "test3");
unset($Array[2]);
The array_pop() function deletes the last element of an array. For more info, you can refer to PHP array_pop
$Array = array("test1", "test2", "test3", "test3");
array_pop($Array);
The array_splice() function removes selected elements from an array and replaces it with new elements. For more info, you can refer to PHP array_splice
$Array = array("test1", "test2", "test3", "test3");
array_splice($Array,1,2);
The array_shift() function removes the first element from an array. For more info, you can refer to PHP array_shift
$Array = array("test1", "test2", "test3", "test3");
array_shift($Array);
If you have to delete multiple values in an array and the entries in that array are objects or structured data, [array_filter][1] is your best bet. Those entries that return a true from the callback function will be retained.
$array = [
['x'=>1,'y'=>2,'z'=>3],
['x'=>2,'y'=>4,'z'=>6],
['x'=>3,'y'=>6,'z'=>9]
];
$results = array_filter($array, function($value) {
return $value['x'] > 2;
}); //=> [['x'=>3,'y'=>6,z=>'9']]
$x = array(1, 2, 3, 4, 5);
var_dump($x);
unset($x[3]); // Here is the key to be deleted
echo '<br>';
array_values($x);
var_dump($x);
Use the following code:
$arr = array('orange', 'banana', 'apple', 'raspberry');
$result = array_pop($arr);
print_r($result);
If you have a numerically indexed array where all values are unique (or they are non-unique but you wish to remove all instances of a particular value), you can simply use array_diff() to remove a matching element, like this:
$my_array = array_diff($my_array, array('Value_to_remove'));
For example:
$my_array = array('Andy', 'Bertha', 'Charles', 'Diana');
echo sizeof($my_array) . "\n";
$my_array = array_diff($my_array, array('Charles'));
echo sizeof($my_array);
This displays the following:
4
3
In this example, the element with the value 'Charles' is removed as can be verified by the sizeof() calls that report a size of 4 for the initial array, and 3 after the removal.
unset() destroys the specified variables.
The behavior of unset() inside of a function can vary depending on what type of variable you are attempting to destroy.
If a globalized variable is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset() was called.
<?php
function destroy_foo()
{
global $foo;
unset($foo);
}
$foo = 'bar';
destroy_foo();
echo $foo;
?>
The answer of the above code will be bar.
To unset() a global variable inside of a function:
<?php
function foo()
{
unset($GLOBALS['bar']);
}
$bar = "something";
foo();
?>
If you have to delete multiple values in an array and the entries in that array are objects or structured data, [array_filter][1] is your best bet. Those entries that return a true from the callback function will be retained.
$array = [
['x'=>1,'y'=>2,'z'=>3],
['x'=>2,'y'=>4,'z'=>6],
['x'=>3,'y'=>6,'z'=>9]
];
$results = array_filter($array, function($value) {
return $value['x'] > 2;
}); //=> [['x'=>3,'y'=>6,z=>'9']]
For associative arrays, use unset:
$arr = array('a' => 1, 'b' => 2, 'c' => 3);
unset($arr['b']);
// RESULT: array('a' => 1, 'c' => 3)
For numeric arrays, use array_splice:
$arr = array(1, 2, 3);
array_splice($arr, 1, 1);
// RESULT: array(0 => 1, 1 => 3)
Using unset for numeric arrays will not produce an error, but it will mess up your indexes:
$arr = array(1, 2, 3);
unset($arr[1]);
// RESULT: array(0 => 1, 2 => 3)
Solutions:
unset($array[3]); unset($array['foo']);
unset($array[3], $array[5]); unset($array['foo'], $array['bar']);
array_splice($array, $offset, $length);
Further explanation:
Using these functions removes all references to these elements from PHP. If you want to keep a key in the array, but with an empty value, assign the empty string to the element:
$array[3] = $array['foo'] = '';
Besides syntax, there's a logical difference between using unset() and assigning '' to the element. The first says This doesn't exist anymore, while the second says This still exists, but its value is the empty string.
If you're dealing with numbers, assigning 0 may be a better alternative. So, if a company stopped production of the model XL1000 sprocket, it would update its inventory with:
unset($products['XL1000']);
However, if it temporarily ran out of XL1000 sprockets, but was planning to receive a new shipment from the plant later this week, this is better:
$products['XL1000'] = 0;
If you unset() an element, PHP adjusts the array so that looping still works correctly. It doesn't compact the array to fill in the missing holes. This is what we mean when we say that all arrays are associative, even when they appear to be numeric. Here's an example:
// Create a "numeric" array
$animals = array('ant', 'bee', 'cat', 'dog', 'elk', 'fox');
print $animals[1]; // Prints 'bee'
print $animals[2]; // Prints 'cat'
count($animals); // Returns 6
// unset()
unset($animals[1]); // Removes element $animals[1] = 'bee'
print $animals[1]; // Prints '' and throws an E_NOTICE error
print $animals[2]; // Still prints 'cat'
count($animals); // Returns 5, even though $array[5] is 'fox'
// Add a new element
$animals[ ] = 'gnu'; // Add a new element (not Unix)
print $animals[1]; // Prints '', still empty
print $animals[6]; // Prints 'gnu', this is where 'gnu' ended up
count($animals); // Returns 6
// Assign ''
$animals[2] = ''; // Zero out value
print $animals[2]; // Prints ''
count($animals); // Returns 6, count does not decrease
To compact the array into a densely filled numeric array, use array_values():
$animals = array_values($animals);
Alternatively, array_splice() automatically reindexes arrays to avoid leaving holes:
// Create a "numeric" array
$animals = array('ant', 'bee', 'cat', 'dog', 'elk', 'fox');
array_splice($animals, 2, 2);
print_r($animals);
Array
(
[0] => ant
[1] => bee
[2] => elk
[3] => fox
)
This is useful if you're using the array as a queue and want to remove items from the queue while still allowing random access. To safely remove the first or last element from an array, use array_shift() and array_pop(), respectively.
Also, for a named element:
unset($array["elementName"]);
For those of you who are looking for Ruby's hash#delete equivalent in PHP:
<?php
function array_delete(&$array, $key) {
if (!isset($array[$key])) {
return null;
}
$value = $array[$key];
unset($array[$key]);
return $value;
}
This will not only delete the element from your array, but it will also return the value stored in that key so you can consume your array in a non-linear fashion.
Solutions:
unset($array[3]); unset($array['foo']);
unset($array[3], $array[5]); unset($array['foo'], $array['bar']);
array_splice($array, $offset, $length);
Further explanation:
Using these functions removes all references to these elements from PHP. If you want to keep a key in the array, but with an empty value, assign the empty string to the element:
$array[3] = $array['foo'] = '';
Besides syntax, there's a logical difference between using unset() and assigning '' to the element. The first says This doesn't exist anymore, while the second says This still exists, but its value is the empty string.
If you're dealing with numbers, assigning 0 may be a better alternative. So, if a company stopped production of the model XL1000 sprocket, it would update its inventory with:
unset($products['XL1000']);
However, if it temporarily ran out of XL1000 sprockets, but was planning to receive a new shipment from the plant later this week, this is better:
$products['XL1000'] = 0;
If you unset() an element, PHP adjusts the array so that looping still works correctly. It doesn't compact the array to fill in the missing holes. This is what we mean when we say that all arrays are associative, even when they appear to be numeric. Here's an example:
// Create a "numeric" array
$animals = array('ant', 'bee', 'cat', 'dog', 'elk', 'fox');
print $animals[1]; // Prints 'bee'
print $animals[2]; // Prints 'cat'
count($animals); // Returns 6
// unset()
unset($animals[1]); // Removes element $animals[1] = 'bee'
print $animals[1]; // Prints '' and throws an E_NOTICE error
print $animals[2]; // Still prints 'cat'
count($animals); // Returns 5, even though $array[5] is 'fox'
// Add a new element
$animals[ ] = 'gnu'; // Add a new element (not Unix)
print $animals[1]; // Prints '', still empty
print $animals[6]; // Prints 'gnu', this is where 'gnu' ended up
count($animals); // Returns 6
// Assign ''
$animals[2] = ''; // Zero out value
print $animals[2]; // Prints ''
count($animals); // Returns 6, count does not decrease
To compact the array into a densely filled numeric array, use array_values():
$animals = array_values($animals);
Alternatively, array_splice() automatically reindexes arrays to avoid leaving holes:
// Create a "numeric" array
$animals = array('ant', 'bee', 'cat', 'dog', 'elk', 'fox');
array_splice($animals, 2, 2);
print_r($animals);
Array
(
[0] => ant
[1] => bee
[2] => elk
[3] => fox
)
This is useful if you're using the array as a queue and want to remove items from the queue while still allowing random access. To safely remove the first or last element from an array, use array_shift() and array_pop(), respectively.
unset($array[$index]);
It should be noted that unset() will keep indexes untouched, which is what you'd expect when using string indexes (array as hashtable), but can be quite surprising when dealing with integer indexed arrays:
$array = array(0, 1, 2, 3);
unset($array[2]);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[3]=>
int(3)
} */
$array = array(0, 1, 2, 3);
array_splice($array, 2, 1);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(3)
} */
So array_splice() can be used if you'd like to normalize your integer keys. Another option is using array_values() after unset():
$array = array(0, 1, 2, 3);
unset($array[2]);
$array = array_values($array);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(3)
} */
Destroy a single element of an array
unset()
$array1 = array('A', 'B', 'C', 'D', 'E');
unset($array1[2]); // Delete known index(2) value from array
var_dump($array1);
The output will be:
array(4) {
[0]=>
string(1) "A"
[1]=>
string(1) "B"
[3]=>
string(1) "D"
[4]=>
string(1) "E"
}
If you need to re index the array:
$array1 = array_values($array1);
var_dump($array1);
Then the output will be:
array(4) {
[0]=>
string(1) "A"
[1]=>
string(1) "B"
[2]=>
string(1) "D"
[3]=>
string(1) "E"
}
Pop the element off the end of array - return the value of the removed element
mixed array_pop(array &$array)
$stack = array("orange", "banana", "apple", "raspberry");
$last_fruit = array_pop($stack);
print_r($stack);
print_r('Last Fruit:'.$last_fruit); // Last element of the array
The output will be
Array
(
[0] => orange
[1] => banana
[2] => apple
)
Last Fruit: raspberry
Remove the first element (red) from an array, - return the value of the removed element
mixed array_shift ( array &$array )
$color = array("a" => "red", "b" => "green" , "c" => "blue");
$first_color = array_shift($color);
print_r ($color);
print_r ('First Color: '.$first_color);
The output will be:
Array
(
[b] => green
[c] => blue
)
First Color: red
unset($array[$index]);
It should be noted that unset() will keep indexes untouched, which is what you'd expect when using string indexes (array as hashtable), but can be quite surprising when dealing with integer indexed arrays:
$array = array(0, 1, 2, 3);
unset($array[2]);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[3]=>
int(3)
} */
$array = array(0, 1, 2, 3);
array_splice($array, 2, 1);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(3)
} */
So array_splice() can be used if you'd like to normalize your integer keys. Another option is using array_values() after unset():
$array = array(0, 1, 2, 3);
unset($array[2]);
$array = array_values($array);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(3)
} */
// Remove by value
function removeFromArr($arr, $val)
{
unset($arr[array_search($val, $arr)]);
return array_values($arr);
}
Two ways for removing the first item of an array with keeping order of the index and also if you don't know the key name of the first item.
// 1 is the index of the first object to get
// NULL to get everything until the end
// true to preserve keys
$array = array_slice($array, 1, null, true);
// Rewinds the array's internal pointer to the first element
// and returns the value of the first array element.
$value = reset($array);
// Returns the index element of the current array position
$key = key($array);
unset($array[$key]);
For this sample data:
$array = array(10 => "a", 20 => "b", 30 => "c");
You must have this result:
array(2) {
[20]=>
string(1) "b"
[30]=>
string(1) "c"
}
It should be noted that unset() will keep indexes untouched, which is what you'd expect when using string indexes (array as hashtable), but can be quite surprising when dealing with integer indexed arrays:
$array = array(0, 1, 2, 3);
unset($array[2]);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[3]=>
int(3)
} */
$array = array(0, 1, 2, 3);
array_splice($array, 2, 1);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(3)
} */
So array_splice() can be used if you'd like to normalize your integer keys. Another option is using array_values() after unset():
$array = array(0, 1, 2, 3);
unset($array[2]);
$array = array_values($array);
var_dump($array);
/* array(3) {
[0]=>
int(0)
[1]=>
int(1)
[2]=>
int(3)
} */
Source: Stackoverflow.com