PHP Manual: max

Description

function max(mixed $value, mixed ...$values): mixed

Alternative signature (not supported with named arguments):

function max(array $value_array): mixed

If the first and only parameter is an array, max() returns the highest value in that array. If at least two parameters are provided, max() returns the biggest of these values.

Note:
Values of different types will be compared using the standard comparison rules. For instance, when a non-numeric string is compared to an int, the int is cast to string and the values are compared as strings; before PHP 8.0.0 the string was cast to int instead. Multiple non-numeric string values are also compared as strings. The actual value returned will be of the original type with no conversion applied.

Caution

Be careful when passing arguments of different types because max() can produce unpredictable results.

Parameters

value: Any comparable value.
values: Any comparable values.
value_array: An array containing the values.

Return Values

max() returns the parameter value considered "highest" according to standard comparisons. If multiple values of different types evaluate as equal (e.g. 0 and false) the first provided to the function will be returned.

Errors/Exceptions

If an empty array is passed, max() throws a ValueError.

Changelog

Version	Description
8.0.0	max() throws a ValueError on failure now; previously, `false` was returned and an `E_WARNING` error was emitted.
8.0.0	As string to number comparisons were changed, max() no longer returns a different value based on the argument order in those cases.

Examples

Example #1 Example uses of max()

<?php
echo max(2, 3, 1, 6, 7), PHP_EOL;  // 7
echo max(array(2, 4, 5)), PHP_EOL; // 5

// 'hello' is a non-numeric string, so -1 is cast to the string "-1" and the
// values are compared as strings: "hello" is greater than "-1"
echo max('hello', -1), PHP_EOL;    // hello

// With multiple arrays of different lengths, max returns the longest
$val = max(array(2, 2, 2), array(1, 1, 1, 1)); // array(1, 1, 1, 1)
var_dump($val);

// Multiple arrays of the same length are compared from left to right
// so in our example: 2 == 2, but 5 > 4
$val = max(array(2, 4, 8), array(2, 5, 1)); // array(2, 5, 1)
var_dump($val);

// If both an array and non-array are given, the array will be returned
// as comparisons treat arrays as greater than any other value
$val = max('string', array(2, 5, 7), 42);   // array(2, 5, 7)
var_dump($val);

// If one argument is NULL or a boolean, it will be compared against
// other values using the rule FALSE < TRUE regardless of the other types involved
// In the below example, -10 is treated as TRUE in the comparison
$val = max(-10, FALSE); // -10
var_dump($val);

// 0, on the other hand, is treated as FALSE, so is "lower than" TRUE
$val = max(0, TRUE); // TRUE
var_dump($val);
?>