Convert an irregular array to a string implode use a string to convert an array to a string

<br><?php
 
$array = array('lastname', 'email', 'phone');
$comma_separated = implode(",", $array);
 
echo $comma_separated; // lastname,email,phone
 
// Empty string when using an empty array:
var_dump(implode('hello', array())); // string(0) ""
 
?>

explode — split one string with another, returning an array

<?php
// example 1
$pizza  = "piece1 piece2 piece3 piece4 piece5 piece6";
$pieces = explode(" ", $pizza);
echo $pieces[0]; // piece1
echo $pieces[1]; // piece2
 
// example 2
$data = "foo:*:1023:1000::/home/foo:/bin/sh";
list($user, $pass, $uid, $gid, $gecos, $home, $shell) = explode(":", $data);
echo $user; // foo
echo $pass; // *
 
?>

Here, if the string does not have any symbols that can be split, other methods need to be considered.

str_split — convert a string to an array

<?php
 
$str = "Hello Friend";
 
$ arr1 = str_split ( $ str );
$ arr2 = str_split ( $ str , 3 );
 
print_r($arr1);
print_r($arr2);
 
?>
output result
Array
(
    [0] => H
    [1] => e
    [2] => l
    [3] => l
    [4] => o
    [5] =>
    [6] => F
    [7] => r
    [8] => i
    [9] => e
    [10] => n
    [11] => d
)
 
Array
(
    [ 0 ] => Hel
    [ 1 ] => it
    [ 2 ] => Fri.
    [3] => end
)

If it is not compatible, you can only consider other methods, breaking the string bit by bit,

Here's a manual way to break a string, which is a method of kana verification in order to write half-width Japanese

Here is an enumeration of a string of half-width pseudonyms

function  kana_Perl ( $ katakana ) {
         
    $katakana_array = array(
        1=>"ｱ",2=>"ｲ",3=>"ｳ",4=>"ｴ",5=>"ｵ",
         
        6=>"ｶ",7=>"ｷ",8=>"ｸ",9=>"ｹ",10=>"ｺ",
         
        11=>"ｻ",12=>"ｼ",13=>"ｽ",14=>"ｾ",15=>"ｿ",
         
        16=>"ﾀ",17=>"ﾁ",18=>"ﾂ",19=>"ﾃ",20=>"ﾄ",
         
        21=>"ﾅ",22=>"ﾆ",23=>"ﾇ",24=>"ﾈ",25=>"ﾉ",
         
        26=>"ﾊ",27=>"ﾋ",28=>"ﾌ",29=>"ﾍ",30=>"ﾎ",
         
        31=>"ﾏ",32=>"ﾐ",33=>"ﾑ",34=>"ﾒ",35=>"ﾓ",
         
        36=>"ﾔ",37=>"ﾕ",38=>"ﾖ",
         
        39=>"ﾗ",40=>"ﾘ",41=>"ﾙ",42=>"ﾚ",43=>"ﾛ",
         
        44=>"ﾜ",45=>"ｦ",46=>"ﾝ",
     
        47=>"ｧ",48=>"ｨ",49=>"ｩ",50=>"ｪ",51=>"ｫ",
         
        52=>"ｬ",53=>"ｭ",54=>"ｮ",55=>"ｯ",56=>"､",
         
        57=>"｡",58=>"ｰ",59=>"ﾞ",60=>"ﾟ"
        );
         
         $check_result   = array_search($katakana,$katakana_array);
          
         return $check_result;
         
    }

This is a matching rule, note that i +=2 here, because a text occupies 2 bits

function substr_cut($katakana){
    $i_end = 2;
    $check_sucess = "";
    for($i_start=0; $i_start < strlen($katakana); $i_start=$i_start+2){
         
        $str_cut = substr($katakana,$i_start,$i_end);
        echo '$str_cut='.$str_cut.'<br>';
        $check_sucess = kana_Perl($str_cut);
        if(!$check_sucess){
            break;
        }
         
 
    }
    return $check_sucess;
}

Convert irregular array to string

function substr_cut($katakana){
    $i_end = 1 ; // Interrupt the length of digits, distinguish between English and Chinese
    $check_sucess = array();
    for($i_start=0; $i_start < strlen($katakana); $i_start=$i_start+1){       
        $str_cut = substr($katakana,$i_start,$i_end);
        $check_sucess[$i_start] = $str_cut;
        echo '$str_cut='.$str_cut.'<br>';
    }
    return $check_sucess;
}