array_unshift() to add one element at beginning of the array in PHP

array_unshift(): Adding one element at starting of the array

$output=array_unshift($input);

Array unshift() to add one element at the beginning of the array

To add one or more element at the beginning of the array. After applying array_unshift() total elements of the array increases by one or more . All numerical array keys are re-indexed but literal keys remain same.

Returns the total number of elements present (after adding using array_unshift() to the array.)

Here $input is an array, $output get the value of total number of elements of the array.

$input=array('One','Two','Three','Four','Five');
$output=array_unshift($input,'added_now');
echo $output; // Output is  6
echo "<br><br>";
while (list ($key, $val) = each ($input)) {
echo "$key -> $val <br>";
}

Output of above code is here( $output gets the number of elements present 6 )

6

0 -> added_now 
1 -> One 
2 -> Two 
3 -> Three 
4 -> Four 
5 -> Five

To add more than one element we will change the code like this.

$output=array_unshift($input,'added_one','add_two');

With Literal Keys

$input=array('Fruits1' =>'Banana','Fruits2'=>'Mango','Fruits3'=>'Apple','Fruits4'=>'Grapes');
$output=array_unshift($input, 'Strawberry');
echo $output; // Output is 5
echo "<br><br>";
while (list ($key, $val) = each ($input)) {
echo "$key -> $val <br>";
}

Output is here, ( $output gets the first element Banana)

5

0 -> Strawberry 
Fruits1 -> Banana 
Fruits2 -> Mango 
Fruits3 -> Apple 
Fruits4 -> Grapes

Now key of the first element is 0. To add one element with key to an associative array we have to use the code below.

$input=array('Fruits1' =>'Banana','Fruits2'=>'Mango','Fruits3'=>'Apple','Fruits4'=>'Grapes');
$input=array('new_fruit'=> 'Strawberry') + $input;
while (list ($key, $val) = each ($input)) {
echo "$key -> $val <br>";
}

Output is here

new_fruit -> Strawberry 
Fruits1 -> Banana 
Fruits2 -> Mango 
Fruits3 -> Apple 
Fruits4 -> Grapes

Using current

By using current() we can get the element to which the present internal pointer is pointing. By defalut it points to first element of the array.

$input=array('Fruits1' =>'Banana','Fruits2'=>'Mango','Fruits3'=>'Apple','Fruits4'=>'Grapes');
echo current($input); 
echo "<br>";
$output=array_unshift($input,'Strawberry');
echo current($input);

Output is here.( The first element is changed from Banana to Mango)

Banana
Strawberry

Array Adding & Removing Elements
array_pop(): Removing Last element of the Array
array_shift(): Removing First element of the Array
array_unset(): Removing element from any position of the Array
array_push(): Adding elements at the end of the Array
array_unshift(): Adding elements at the beginning of the Array

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