Question

我需要检查字符串是否有简单的方程式并显示结果。

示例：

$string = 'Hello world'; // not math
$string = '100 + 10?'; // Results should be 110
$string = 'What is 10 + 5'; // Results should be 15
$string = '1*1=?'; // Results should be 1
$string = 'what is one plus one'; // Results should be 2

字符串可以包含字母，数字和字符

我试过

$string = 'What is 10 + 5';    
$test = preg_replace('/[^0-9,\-\+\*\/]/', "", $string); // 10+5

我不确定如何计算结果并检查字符串是否有数学

解决：我使用此代码

 if(preg_match('/[0-9\-\+\*\/]/', $string)){
        $test = preg_replace('/[^0-9,\-\+\*\/]/', "", $string);
        if(preg_match('/(\d+)(?:\s*)([\+\-\*\/])(?:\s*)(\d+)/', $test, $matches) !== FALSE){
            $operator = $matches[2];
            switch($operator){
                case '+':
                    $p = $matches[1] + $matches[3];
                    break;
                case '-':
                    $p = $matches[1] - $matches[3];
                    break;
                case '*':
                    $p = $matches[1] * $matches[3];
                    break;
                case '/':
                    $p = $matches[1] / $matches[3];
                    break;
            }
            $test = $p;
        }
        $data['response'] = $test;
    }

Answer 1

除了最后一个字符串之外，它将处理所有字符串。

    $mixed = "100 + 10?";
    $letters=array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V','W', 'X', 'Y', 'Z','?','=');
    $only_numbers=str_replace($letters, '', $mixed);

    echo "$only_numbers <br>";

    $only_numbers = eval('return '.$only_numbers.';');

    echo "$only_numbers <br>";

请参阅：calculate math expression from a string using eval

检查字符串是否包含PHP和echo结果中的等式

1 个答案: