假设您有一个数字数组（您没有指定），您可以使用rsort()按照您要查找的正确顺序对数字进行排序。
如果你同意排名从0开始：

<?php

$numbers = [30, 874, 320, 940, 1149]; // your numbers

// Sort the numbers in descending order
rsort($numbers);

print_r(array_flip($numbers));

结果：

Array
(
    [1149] => 0
    [940] => 1
    [874] => 3
    [320] => 2
    [30] => 4
)

如果你想让他们1：

<?php

$numbers = [30, 874, 320, 940, 1149]; // your numbers

// Sort the numbers in descending order
rsort($numbers);

// Assign ranks
$ranks = [];

for ($i = 1; $i <= count($numbers); $i++) {
    $ranks[$numbers[$i-1]] = $i;
}

print_r($ranks);

输出：

Array
(
    [1149] => 1
    [940] => 2
    [874] => 3
    [320] => 4
    [30] => 5
)