How to Determine the Depth of a Multidimensional PHP Array?

Determining the Depth of a Multidimensional PHP Array

PHP arrays can contain nested arrays, creating complex hierarchical structures. Determining the maximum depth of nesting within these arrays can be essential for data analysis and manipulation.

Function to Calculate Array Depth

One approach to determine the depth of an array is to recursively traverse its elements, counting the number of levels. The following function, array_depth(), takes an array as an input and calculates its maximum depth:

function array_depth($array) {
    $max_depth = 0;

    foreach ($array as $element) {
        if (is_array($element)) {
            $depth = $array_depth($element);
            if ($depth > $max_depth) {
                $max_depth = $depth;
            }
        }
    }

    return $max_depth + 1;
}

In this function:

• The is_array() check ensures that nested elements are processed recursively.
• The depth is incremented by 1 for each level of nesting.
• The final returned value represents the maximum depth of the array.

Alternative Approach Using print_r()

Another method avoids the potential issue of infinite recursion. It utilizes the indentation in the output of print_r(), which reflects the array's structure. The array_depth() function below uses this approach:

function array_depth($array) {
    $max_indentation = 1;

    $array_str = print_r($array, true);
    $lines = explode("\n", $array_str);

    foreach ($lines as $line) {
        $indentation = (strlen($line) - strlen(ltrim($line))) / 4;

        if ($indentation > $max_indentation) {
            $max_indentation = $indentation;
        }
    }

    return ceil(($max_indentation - 1) / 2) + 1;
}

• print_r() converts the array into a string with indented lines for each level.
• The explode() function splits the string into lines.
• The indentation for each line is calculated and compared to the maximum indentation.
• The maximum indentation (divided by 2) represents the array's depth, as each indentation level indicates a depth increase of 1.

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