How to replace two-dimensional array in php

In PHP, array is a very common and useful data structure. Two-dimensional arrays add one dimension to one-dimensional arrays, allowing for more flexible storage and manipulation of data. However, in actual applications, we may need to perform a replacement operation on a two-dimensional array, such as replacing a certain value in the array, and this replacement operation needs to be implemented in multiple sub-arrays at the same time. This article will introduce how to replace a two-dimensional array in PHP.

1. Replace a single value in a two-dimensional array

In PHP, we can use the array_replace() function to replace a single value in an array. This function accepts multiple arrays as parameters and returns a new array after replacement. For example, we have the following two-dimensional array:

$arr = array(
   array('name' => 'Tom', 'age' => 18),
   array('name' => 'Jack', 'age' => 20),
   array('name' => 'Mary', 'age' => 22)
);

If we need to change the information named "Tom" to "Peter", we can use the array_replace() function to achieve this:

$newArr = array_replace($arr[0], array('name' => 'Peter'));
$arr[0] = $newArr;

The above code , we first use the array_replace() function to replace the information named "Tom" with the information named "Peter", and assign the replaced new array to the $newArr variable. Then, we assign $newArr back to the original array again, realizing the operation of replacing an element in the two-dimensional array.

2. Replace multiple values ​​in the two-dimensional array

If we need to replace the same values ​​in multiple sub-arrays in the two-dimensional array, we can use the array_map() function to traverse array and replace it. An example is as follows:

$array = array(
 array('name' => 'Tom', 'age' => 18, 'sex' => 'M'),
 array('name' => 'Jack', 'age' => 20, 'sex' => 'M'),
 array('name' => 'Mary', 'age' => 22, 'sex' => 'F')
);

function replace_name($array) {
 $array['name'] = 'Peter';
 return $array;
}

$new_arr = array_map('replace_name', $array);

In the above code, we define a function named replace_name, which accepts an array as a parameter and changes the value corresponding to the "name" key in the array to "Peter" return. We then use the array_map() function to apply the function to each sub-array of the original array and assign the processed results to the $newArr variable. Finally, we can use the print_r() function to output the contents of the new array to the screen for viewing.

3. Use references to implement replacement

In PHP, you can use references (&) to change the value of the actual parameter in a function call. Therefore, we can also use references to replace data in a two-dimensional array. For example:

$array = array(
 array('name' => 'Tom', 'age' => 18, 'sex' => 'M'),
 array('name' => 'Jack', 'age' => 20, 'sex' => 'M'),
 array('name' => 'Mary', 'age' => 22, 'sex' => 'F')
);

function replace_name(&$array) {
 $array['name'] = 'Peter';
}

foreach($array as &$value) { replace_name($value); }

In the above code, we define a replace_name function that uses a reference to pass an array as a parameter and replaces the "name" key in the array with "Peter". We then iterate through the original array through a foreach loop and pass each element in turn to the replace_name function using a reference. Finally, the value corresponding to the "name" key in the original array was successfully replaced with "Peter".

In summary, to replace a two-dimensional array in PHP, you can use the array_replace() function, array_map() function, or pass parameters by reference and achieve it through a loop. Different methods are suitable for different scenarios, and you can choose flexibly according to the actual situation.

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