How to set the value in an array in php

In PHP programming, it is often necessary to operate on arrays, including adding, deleting, modifying, searching, etc. of arrays. This article will explain how to set values ​​in an array in PHP.

1. Use the equal sign (=) to assign a value

In PHP, you can use the equal sign (=) assignment symbol to directly assign a value to an element in the array, for example:

$array = array('foo', 'bar');
$array[0] = 'newfoo';
var_dump($array);

After executing the above code, the output result is:

array(2) {
  [0]=>
  string(6) "newfoo"
  [1]=>
  string(3) "bar"
}

As you can see, the first element of the array has been modified to "newfoo".

2. Use the array_splice() function to insert elements

In addition to using the equal sign (=) assignment symbol to modify the array element value, you can also use the array_splice() function to insert element. The syntax of this function is as follows:

array_splice(array &$input, int $offset [, int $length = count($input), mixed $replacement = array()]) : array

This function receives four parameters:

• array &$input: the array to be operated on;
• int $offset: to be The index position of the inserted element;
• int $length: optional parameter, specifies the number of elements to be deleted. The default value is the array length;
• mixed $replacement: the element to be inserted. If this parameter is not specified, the specified number of elements will be deleted. If specified, the element will be inserted at the specified position.

For example, if you want to insert an element "value" after the second element of an array (index 1), you can use the following code:

$array = array('foo', 'bar', 'baz');
array_splice($array, 1, 0, 'value');
var_dump($array);

After executing the above code , the output result is:

array(4) {
  [0]=>
  string(3) "foo"
  [1]=>
  string(5) "value"
  [2]=>
  string(3) "bar"
  [3]=>
  string(3) "baz"
}

As you can see, an element "value" is inserted after the second element in the array (index 1).

3. Use the [] operator to add elements

In addition to using the equal sign (=) assignment symbol and the array_splice() function to insert elements, you can also use the [] operator to add elements. This operator will automatically add elements to the end of the array, for example:

$array = array('foo', 'bar');
$array[] = 'baz';
var_dump($array);

After executing the above code, the output result is:

array(3) {
  [0]=>
  string(3) "foo"
  [1]=>
  string(3) "bar"
  [2]=>
  string(3) "baz"
}

You can see that an element is added to the end of the array "baz".

4. Use the array_push() function to add elements

In addition to using the [] operator to add elements, you can also use the array_push() function to add elements. The syntax of this function is as follows:

array_push(array &$array, mixed $value1 [, mixed $value2…]) : int

This function receives one or more parameters:

• array &$array: the array to be operated on;
• mixed $value1 : The first element to be added;
• mixed $value2: Optional parameter, the second element to be added;
• ...: By analogy, any number of elements can be added.

For example, if you want to add elements "value1" and "value2" to an array, you can use the following code:

$array = array('foo', 'bar');
array_push($array, 'value1', 'value2');
var_dump($array);

After executing the above code, the output result is:

array(4) {
  [0]=>
  string(3) "foo"
  [1]=>
  string(3) "bar"
  [2]=>
  string(6) "value1"
  [3]=>
  string(6) "value2"
}

As you can see, two elements "value1" and "value2" were added to the array.

5. Use the array_unshift() function to add elements

Similar to the array_push() function, there is also a function array_unshift() that can be used to add elements to the beginning of the array. The syntax of this function is as follows:

array_unshift(array &$array, mixed $value1 [, mixed $value2…]) : int

This function receives one or more parameters:

• array &$array: the array to be operated on;
• mixed $value1 : The first element to be added;
• mixed $value2: Optional parameter, the second element to be added;
• ...: By analogy, any number of elements can be added.

For example, if you want to add elements "value1" and "value2" to the beginning of an array, you can use the following code:

$array = array('foo', 'bar');
array_unshift($array, 'value1', 'value2');
var_dump($array);

After executing the above code, the output result is:

array(4) {
  [0]=>
  string(6) "value1"
  [1]=>
  string(6) "value2"
  [2]=>
  string(3) "foo"
  [3]=>
  string(3) "bar"
}

As you can see, two elements "value1" and "value2" are added to the beginning of the array.

The above is the method of setting the value in the array in PHP. You can choose to use it according to the actual situation.

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