Comparing Array Unshift() to Array Push()

When it comes to manipulating arrays in PHP, there are several methods available for adding new elements to an existing array structure. Two of the most commonly used functions for doing so are `array_unshift()` and `array_push()`. While both functions can be used to add elements to an array, they work in slightly different ways.

Array Unshift()

`array_unshift()` is a PHP function that allows you to add one or more elements to the beginning of an array. This means that any existing elements in the array will be shifted down to make room for the new elements. The original array indices are preserved, but they may change as a result of the insertion.

One key difference between `array_unshift()` and `array_push()` is that `array_unshift()` will prepend the new element(s) to the start of the array, whereas `array_push()` adds the new element(s) to the end of the array.

Multidimensional Arrays

`array_unshift()` works seamlessly with multidimensional arrays. When used on a multidimensional array, it will insert the new elements at the beginning of the top-level array, and then recursively apply itself to any nested arrays that may be present.

For example:

```

$matrix = '

'1, 2',

'3, 4'

array_unshift($matrix, ''a', 'b'');

print_r($matrix);

```

This would output:

```

Array

(

'0' => Array

(

'0' => a

'1' => b

)

'1' => Array

(

'0' => 1

'1' => 2

)

'2' => Array

(

'0' => 3

'1' => 4

)

```

Associative Arrays

When used on an associative array, `array_unshift()` will generate new numeric keys starting from 0. This means that any existing key-value pairs will be shifted down to make room for the new elements.

For example:

```

$user = ''name' => 'John'';

array_unshift($user, 'Review email');

print_r($user);

```

This would output:

```

Array

(

'0' => Review email

'name' => John

)

```

Usage with Indexed Arrays

`array_unshift()` is commonly used with indexed arrays to insert new elements at the start. This can be particularly useful in situations where you need to add a new element to an array that has already been populated.

For example:

```

$tasks = '1, 2, 3';

array_unshift($tasks, 0);

print_r($tasks);

```

This would output:

```

Array

(

'0' => 0

'1' => 1

'2' => 2

'3' => 3

)

```

Adding Single vs Multiple Values

`array_unshift()` allows you to prepend a single value or multiple values at the same time. This can be particularly useful when you need to add multiple elements to an array in a single operation.

For example:

```

$nums = '1, 2';

array_unshift($nums, 'a', 'b');

print_r($nums);

```

This would output:

```

Array

(

'0' => a

'1' => b

'2' => 1

'3' => 2

)

```

In this comprehensive tutorial, we've taken an in-depth look at how to use `array_unshift()` in PHP. We've explored its usage with indexed arrays, associative arrays, and multidimensional arrays, as well as its ability to add single or multiple values to an array in a single operation. With `array_unshift()`, you can easily prepend new elements to an existing array structure, making it a valuable tool in your PHP development toolkit.

Php array unshift