doushi6947
2015-10-29 17:09
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php将字符串转换为条件语句

I have a bi dimensional array of array with homogeneous values.

$input = array(
     'x' => 100, 'y' => 101, 'type' => 'yes', value => 10
), array(
     'x' => 110, 'y' => 101, 'type' => 'no', value => 10
), array(
     'x' => 120, 'y' => 102, 'type' => 'yes', value => 99
);

I need to find out a way to write a function to filter values passing a "text" filter as input:

//extract all values when $tye = yes and $value is greater than 10
custom_filter($input, "type = yes and value > 10");

//extract all values when $x is equal to $y
custom_filter($input, "x = y");

//filter all values for x is pair and y is odd
custom_filter($input, "x % 2 = 0 and y % 2 > 0");  

function custom_filter($input_array, $condition) {
     (...)
}

Is there a way to "translate" $condition parameter from human readable statement to a php conditional statement?

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1条回答 默认 最新

  • douduan5086 2015-10-29 17:28
    已采纳

    I think this is the easiest way:

    $input = [
         ['x' => 100, 'y' => 101, 'type' => 'yes', 'value' => 10],
         ['x' => 110, 'y' => 101, 'type' => 'no', 'value' => 10],
         ['x' => 120, 'y' => 102, 'type' => 'yes', 'value' => 99]
    ];
    
    function custom_filter($array, $eval) {
        $validate = function ($item) use($eval) {
            extract($item);
            eval('$valid = ' . $eval . ';');
    
            return $valid;
        };
    
        return array_filter($array, $validate);
    }
    
    //extract all values when $tye = yes and $value is greater than 10
    var_dump(custom_filter($input, '$type == "yes" && $value > 10'));
    
    //extract all values when $x is equal to $y
    var_dump(custom_filter($input, '$x == $y'));
    
    //filter all values for x is pair and y is odd
    var_dump(custom_filter($input, '$x % 2 == 0 && $y % 2 > 0'));
    

    Well, you have to write a php code as a condition for extracted values.

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