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How do you flatten multidimensional arrays in PHP into a two-dimensional array with dot notation keys?
How do you flatten multidimensional arrays in PHP into a two-dimensional array with dot notation keys?
Converting Multidimensional Arrays to 2D Arrays with Dot Notation Keys in PHP
Multidimensional arrays in PHP provide a convenient way to organize complex data structures. However, sometimes it may become necessary to flatten a multidimensional array into a two-dimensional array with dot notation keys. This can be achieved using a recursive approach.
Consider the following example:
<code class="php">$myArray = [
'key1' => 'value1',
'key2' => [
'subkey' => 'subkeyval'
],
'key3' => 'value3',
'key4' => [
'subkey4' => [
'subsubkey4' => 'subsubkeyval4',
'subsubkey5' => 'subsubkeyval5',
],
'subkey5' => 'subkeyval5'
]
];</code>To convert this array into a two-dimensional array with dot notation keys, we can use the following code:
<code class="php">$ritit = new RecursiveIteratorIterator(new RecursiveArrayIterator($myArray));
$result = [];
foreach ($ritit as $leafValue) {
$keys = [];
foreach (range(0, $ritit->getDepth()) as $depth) {
$keys[] = $ritit->getSubIterator($depth)->key();
}
$result[join('.', $keys)] = $leafValue;
}</code>This code iterates recursively over the multidimensional array, using the RecursiveIteratorIterator and RecursiveArrayIterator classes. For each leaf value in the array, it creates a dot notation key by joining the keys of the parent and child arrays. The result is a new two-dimensional array with dot notation keys, as shown below:
<code class="php">[
'key1' => 'value1',
'key2.subkey' => 'subkeyval',
'key3' => 'value3',
'key4.subkey4.subsubkey4' => 'subsubkeyval4',
'key4.subkey4.subsubkey5' => 'subsubkeyval5',
'key4.subkey5' => 'subkeyval5'
]</code>This technique can be particularly useful when working with data that needs to be converted to a flat structure for processing or display.
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