如何忽略区分大小写并计算数组值？

Question

无论大小写敏感，计算数组值的最简单方法是什么？试图$arr=array("A","B","b","A","b", "a", "A");print_r(array_count_values($arr));或者：$arr=array("AliCE","Alice","bob","AlICE","BOB", "aLIce", "alice");print_r(array_count_values($arr));演示电流输出Array(    [A] => 3    [B] => 1    [b] => 2    [a] => 1)期望输出Array(    [A] => 4    [B] => 2)或者：Array(    [a] => 4    [b] => 2)

Answer 1

我会使用array_map但作为替代，加入一个字符串，更改大小写，拆分为一个数组：

print_r(array_count_values(str_split(strtolower(implode($arr)))));

Answer 2

您可以先使用strtoupper以下方法将字母映射为大写：

$arr = array("A","B","b","A","b", "a", "A");

print_r(array_count_values(array_map('strtoupper', $arr)));

输出：

(

    [A] => 4

    [B] => 3

)

Answer 3

您可以使用foreach与array_key_exists和strtoupper

$arr=array("A","B","b","A","b", "a", "A");

$res = [];

foreach($arr as $k => $v){

    array_key_exists(strtoupper($v), $res) ? ($res[strtoupper($v)]++) : ($res[strtoupper($v)] = 1); 

}

print_r($res);