PHP/explode()

解説 文字列を配列に変換

explode("区切り文字", $String)

sample1 Array ( [0] => bbb [1] => ccc [2] => ddd )
sample1code
$s1Str = "bbbacccaddd";
$s1Array = explode("a", $s1Str);
print_r($s1Array);