The three methods in php count the number of each character in a string and sort it

 
<?php 
// This method is purely a back function, no explanation;  
function countStr($str){ 
$str_array=str_split($str); 
$str_array=array_count_values($str_array); 
arsort($str_array); 
return $str_array; 
} 
// Here are some examples;  
$str="asdfgfdas323344##$\$fdsdfg*$**$*$**$$443563536254fas"; 
print_r(countStr($str)); 
?> 
<? 
// This method has some data structure ideas, but it's easy to understand :)  
function countStr2($str){ 
$str_array=str_split($str); 
$result_array=array(); 
foreach($str_array as $value){// To determine if the character is a new type, set it to 1 If not, then add;  
if(!$result_array[$value]){ 
$result_array[$value]=1; 
}else{ 
$result_array[$value]++; 
} 
} 
arsort($result_array); 
return $result_array; 
} 
$str="asdfgfdas323344##$\$fdsdfg*$**$*$**$$443563536254fas"; 
var_dump(countStr2($str)) 
?> 
<?php 
// This method is purely a solution 1 The crappy version, first find all the characters of the total class, then in 1 a 1 with substr_count Functional statistics.  
function countStr3($str){ 
$str_array=str_split($str); 
$unique=array_unique($str_array); 
foreach ($unique as $v){ 
$result_array[$v]=substr_count($str,$v); 
} 
arsort($result_array); 
return $result_array; 
} 
$str="asdfgfdas323344##$\$fdsdfg*$**$*$**$$443563536254fas"; 
var_dump(countStr3($str)); 
?> 

* no matter which method you use, you need to use str_split function, so this function is very important