How to remove the key of a two-dimensional array in php

In PHP development, it is often necessary to operate array data. PHP arrays come in two forms: indexed arrays and associative arrays. Usually we use two-dimensional arrays (including multiple associative arrays) when writing code. At this time, if the key names of the two-dimensional array are not needed, we need to remove the key names from the two-dimensional array. This article will introduce some simple methods to accomplish this task.

1. Use the array_values ​​function

Using the array_values ​​function can easily remove the key name of the two-dimensional array. The following is a sample code:

$person = array( 
    array("name" => "Tom", "age" => 20, "gender" => "Male"), 
    array("name" => "Lily", "age" => 18, "gender" => "Female"), 
    array("name" => "Jane", "age" => 22, "gender" => "Female") 
); 

$person = array_map('array_values', $person);

In the above code, we first define a two-dimensional array containing three associative arrays. Then, through the array_map function and array_values ​​function, the key name is removed from each associative array in the two-dimensional array. Explain the array_map function. Its function is to apply the given function to each element of the array and return a new array.

Now we can use the print_r function to output the array with the key name removed:

Array
(
    [0] => Array
        (
            [0] => Tom
            [1] => 20
            [2] => Male
        )

    [1] => Array
        (
            [0] => Lily
            [1] => 18
            [2] => Female
        )

    [2] => Array
        (
            [0] => Jane
            [1] => 22
            [2] => Female
        )

)

As can be seen from the output results, each associative array in the two-dimensional array has the key name removed.

2. Use a loop

Another method is to use a loop to obtain the values ​​of the associative array one by one and save them to a new index array. The following is a sample code:

$person = array( 
    array("name" => "Tom", "age" => 20, "gender" => "Male"), 
    array("name" => "Lily", "age" => 18, "gender" => "Female"), 
    array("name" => "Jane", "age" => 22, "gender" => "Female") 
); 

$newPerson = array(); 

foreach ($person as $p) { 
    $newPerson[] = array_values($p); 
} 

print_r($newPerson);

In the above code, we use a foreach loop to traverse the two-dimensional array $person, take out an associative array each time, and then remove its key name through the array_values ​​function and save it to a new Index into array $newPerson.

Now we can use the print_r function to output the array after removing the key name:

Array
(
    [0] => Array
        (
            [0] => Tom
            [1] => 20
            [2] => Male
        )

    [1] => Array
        (
            [0] => Lily
            [1] => 18
            [2] => Female
        )

    [2] => Array
        (
            [0] => Jane
            [1] => 22
            [2] => Female
        )

)

Compared with the first method, this method is more cumbersome, but it is also more flexible, because we can Perform some other operations in the loop.

Summary

In PHP development, operating arrays is very common. Removing the key names of a two-dimensional array is a common requirement and is relatively easy to implement. This article introduces two methods of removing key names of two-dimensional arrays using the array_values ​​function and looping. Either way, we can choose according to our needs in some special cases.

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