我想在这个循环中只得到我的数组的精确结果：

<?php

        $color_groups = [
            "green" => array('lightgreen', 'green', 'olive', 'malachite'),
            "blue" => array('blue', 'skyblue', 'cyan', 'iris', 'navyblue', 'zaffre')
        ];

        $selected_color_str = 'cyan';

        foreach ($color_groups as $key => $value) {
            foreach ($value as $color) {
                if (preg_match('/' . $color . '/i', $selected_color_str)) {
                    echo $key;
                } else {
                    echo " not_found ";
                }
            }
        }

        ?>

结果：

not_found not_found not_found not_found not_found not_found not_found蓝色not_found not_found not_found not_found

• 但我想只显示blueif exists in that array，if not just echo not_found