如何使用正则表达式检测php上数学运算符上的所有符号？

Question

how to detect all symbol on mathematical operators on php using regex?

example :

$operators = [">0",">=1","==12","<9","<=1","!=4"];
$results = array();
foreach ($operators as $key => $value){
  detect $value using regex, if include symbol of maths operators {
    array_push($results, $value);
    // just push $value with format of symbol of maths operators, example : ">" // remove 0 on my string
  }
}

from my array i want to collect just math operators, my expected results:

$results = [">",">=","==","<","<=","!="];

how to do that? thank you advanced

Answer 1

You can simply use array_map along with preg_replace like as

$operators = [">0", ">=1", "==12", "<9", "<=1", "!=4"];
print_r(array_map(function($v) {
            return preg_replace('/[^\D]/', '', $v);
        }, $operators));

Output:

Array
(
    [0] => >
    [1] => >=
    [2] => ==
    [3] => <
    [4] => <=
    [5] => !=
)

Demo