How to change array cell value in php

In PHP, array is a very common data structure that can save a set of related data and can easily operate and process these data. Sometimes, we need to change the value of an array unit in the code. Here are several implementation methods.

1. Use the index value to change the value of the array unit

In PHP, the array unit is accessed and modified through a unique index value. If we know the index value of a cell, we can easily change its value using an assignment statement. The following is an example:

<?php //声明一个数组
$myArray = array("apple", "banana", "pear", "kiwi");

//改变数组第2个单元的值
$myArray[1] = "orange";

//输出数组
print_r($myArray);
?>

Run the above code, the output result is:

Array
(
    [0] => apple
    [1] => orange
    [2] => pear
    [3] => kiwi
)

As you can see, we successfully changed the value of the second unit of the array to "orange".

2. Use the loop structure to change the values ​​of multiple units of the array

If you want to change the values ​​of multiple units of the array, it will be more convenient and simple to use the loop structure. The following is an example:

<?php //声明一个数组
$myArray = array("apple", "banana", "pear", "kiwi");

//使用循环结构改变数组的前2个单元的值
for($i=0; $i<2; $i++){
    $myArray[$i] = "orange";
}

//输出数组
print_r($myArray);
?>

Run the above code, the output result is:

Array
(
    [0] => orange
    [1] => orange
    [2] => pear
    [3] => kiwi
)

As you can see, we successfully changed the values ​​​​of the first two cells of the array to "orange".

3. Use array functions to change the value of array cells

PHP provides multiple built-in array functions, which can easily perform various operations on arrays, such as deleting, adding, sorting, and searching. etc. Here are some commonly used array functions to change the values ​​of array cells.

1. array_replace()

The array_replace function can be used to replace the value of a cell in an array with the value of the corresponding cell in another array. The following is an example:

<?php //声明一个数组
$myArray1 = array("apple", "banana", "pear", "kiwi");
$myArray2 = array(1=>"orange", 2=>"grape");

//使用array_replace函数替换数组单元的值
$myArray = array_replace($myArray1, $myArray2);

//输出数组
print_r($myArray);
?>

Run the above code, the output result is:

Array
(
    [0] => apple
    [1] => orange
    [2] => grape
    [3] => kiwi
)

As you can see, we successfully replaced the second unit of array 1 with the first unit of array 2. The value "orange" of the cells replaces the third cell of array 1 with the value "grape" of the second cell of array 2.

2. array_walk()

The array_walk function can be used to perform customized operations on the cells of the array, such as modifying the value of the cell. The following is an example:

<?php //声明一个数组
$myArray = array("apple", "banana", "pear", "kiwi");

//使用array_walk函数修改数组单元的值
function changeValue(&$value, $key){
    if($value=="banana") $value="orange";
}

array_walk($myArray, "changeValue");

//输出数组
print_r($myArray);
?>

Run the above code, the output result is:

Array
(
    [0] => apple
    [1] => orange
    [2] => pear
    [3] => kiwi
)

As you can see, we successfully changed the value "banana" of the second unit of the array to " orange".

To sum up, PHP provides a variety of methods for changing the value of an array unit. Developers can choose different methods to modify the value of an array unit according to actual needs.

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