How to dynamically add values ​​to a two-dimensional array in PHP

In PHP, a two-dimensional array is an array containing multiple arrays, each element containing multiple values. It is commonly used to store data sets such as tables, maps, matrices, etc., where values ​​can be added dynamically when needed.

This article will introduce how to dynamically add values ​​to a two-dimensional array in PHP.

1. Create a two-dimensional array

First, you need to create an empty two-dimensional array, its structure is as follows:

$myArray = array(
    array(),
    array(),
    array(),
    // ...
);

Created here A two-dimensional array containing 3 empty arrays. You can also add as many elements to the internal array as you need.

2. Add values ​​directly

You can use the index key name to add values ​​to the two-dimensional array. Suppose you want to add elements to the first array, the code looks like this:

$myArray[0][] = 'value1';
$myArray[0][] = 'value2';
$myArray[0][] = 'value3';

Empty square brackets are used here to add the value to the end of the array using the nearest key. Then, add the new value to the array. Values ​​can be added to other arrays by using different index key names.

3. Use key names to add values

In a two-dimensional array, you can use key names to add values. This is more flexible than using index key names directly because it allows you to specify key names freely.

$myArray = array(
    'array1' => array(),
    'array2' => array(),
    'array3' => array()
);

$myArray['array1']['key1'] = 'value1';
$myArray['array1']['key2'] = 'value2';
$myArray['array1']['key3'] = 'value3';

Here an associative array containing three arrays is created. Then, three elements were added to the first array.

Another advantage of using key names to add values ​​is that you can delete specified elements from the array without affecting the positions of other elements. Elements can be removed using the unset() function.

unset($myArray['array1']['key2']);

4. Add values ​​using loops

Loops are a powerful tool that can greatly simplify your code. If you need to add multiple values ​​to a two-dimensional array, it's better to use a loop.

$myArray = array(
    array(),
    array(),
    array()
);

for ($i = 0; $i < 3; $i++) {
    for ($j = 0; $j < 3; $j++) {
        $myArray[$i][$j] = rand(1, 10);
    }
}

Two nested loops are used here to add random values ​​to each array element.

Summary

The two-dimensional array in PHP is very flexible and can dynamically add values ​​using indexes, key names, loops and other methods. No matter which method you need to use, just follow the corresponding syntax to easily add values ​​to a two-dimensional array.

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