PHPで文字列を分割する

シングルバイト

等分

chunk_split

var_dump(chunk_split("ab\nadefqp", 2, '/'));

string(14) "ab/
a/de/fq/p/"

str_split

var_dump(str_split("ab\nadefqp", 2));

array(5) {
  [0]=>
  string(2) "ab"
  [1]=>
  string(2) "
a"
  [2]=>
  string(2) "de"
  [3]=>
  string(2) "fq"
  [4]=>
  string(1) "p"
}

マルチバイト

等分

preg_match_all('/[\s\S]{1,2}/u', "ああ\n😂defqp", $matches);
var_dump($matches[0]);

preg_match_all('/[\s\S]{1,5}/u', "ああ\n😂defqp", $matches);
var_dump($matches[0]);

preg_match_all('/[\s\S]{1,6}/u', "ああ\n😂defqp", $matches);
var_dump($matches[0]);

array(5) {
  [0]=>
  string(6) "ああ"
  [1]=>
  string(5) "
😂"
  [2]=>
  string(2) "de"
  [3]=>
  string(2) "fq"
  [4]=>
  string(1) "p"
}
array(2) {
  [0]=>
  string(12) "ああ
😂d"
  [1]=>
  string(4) "efqp"
}
array(2) {
  [0]=>
  string(13) "ああ
😂de"
  [1]=>
  string(3) "fqp"
}

指定数で分割

20180102 ⇒ 2018/01/02

$string = '20180102';

// mb_substr
$list = [
    mb_substr($string, 0, 4),
    mb_substr($string, 4, 2),
    mb_substr($string, 6, 2),
];

var_dump(implode('/', $list));


// regular expression
preg_match('/([0-9]{4})([0-9]{2})([0-9]{2})/u', $string, $matches);
array_shift($matches);

var_dump(implode('/', $matches));

string(10) "2018/01/02"
string(10) "2018/01/02"

特定文字で分割

2018/01/02 23:59:00 ⇒ 2018 01 02 23 59 00

mb_split

$string = '2018/01/02 23:59:00';

var_dump(mb_split('[/ :]', $string));

array(6) {
  [0]=>
  string(4) "2018"
  [1]=>
  string(2) "01"
  [2]=>
  string(2) "02"
  [3]=>
  string(2) "23"
  [4]=>
  string(2) "59"
  [5]=>
  string(2) "00"
}

preg_split

$string = '2018/01/02 23:59:00';

var_dump(preg_split('/[\/ :]/u', $string));

array(6) {
  [0]=>
  string(4) "2018"
  [1]=>
  string(2) "01"
  [2]=>
  string(2) "02"
  [3]=>
  string(2) "23"
  [4]=>
  string(2) "59"
  [5]=>
  string(2) "00"
}

explode