比较两个相同的字符串在PHP中返回false

Question

这个完全超出我的范围.我想比较两个字符串.当我回显它们时,它们似乎是相同的,但当我将它们与'=='运算符进行比较时,它返回false.例如,在我的数据库上运行下面的代码时.它输出的东西像"显然苹果不等于苹果".任何人都可以对此有所了解吗？

if ($this->data['list_text']) { //user has entered into textarea
            $list = nl2br($this->data['list_text']);

            $list_array = explode('<br />',$list);

            $ranking = 1;
            $company_array = $this->CompanyList->CompanyRanking->Company->find('list',null);

            //this is the comparison bit
            foreach ($list_array as $key => $value) {
                $companyId = null;
                foreach ($company_array as $key2 => $value2) {
                    if ($value2 != $value) {
                        echo 'APPARENTLY '.$value2.' does not equal '.$value;                           
                    } else {
                        $companyId = $key2;
                        break;
                    }
                }

                $this->data['CompanyRanking'][$ranking]['ranking'] = $ranking;
                $this->data['CompanyRanking'][$ranking]['company_id'] = $companyId;
                $ranking++;
            }
        }

Answer 1

尝试使用var_dump()而不是echo.

echo 'APPARENTLY '.$value2.' does not equal '.$value;   
echo '<pre>Debug: ';
echo 'value='; var_dump($value);
echo 'value2='; var_dump($value2);
echo '</pre>';

它提供了额外的信息.例如实际类型.和弦的长度.

Answer 2

我同意奥拉维尔的观点。我删除了修剪并将其替换为 preg_replace 因为您假设 $value 和 $value2 是 companyID。如果 companyID 应该是字母数字、包含连字符等，您可以对这些进行快速修改...这个版本应该可以做到这一点：

if ($this->data['list_text']) { 
    $list = nl2br($this->data['list_text']);
    $list_array = explode('<br />', $list);

    $ranking = 1;
    $company_array = $this->CompanyList->CompanyRanking->Company->find('list',null);

    foreach ($list_array as $key => $value) {

        // remove any non digit characters
        $value = preg_replace('/[^0-9]/i','', $value); 
        $companyId = null;

        foreach ($company_array as $key2 => $value2) {

            // remove any non digit characters
            $value2 = preg_replace('/[^0-9]/i','', $value2); 

            if ($value2 != $value) {
                echo 'values not equal';                
            } else {
                $companyId = $key2;
                break;
            }
        }

        $this->data['CompanyRanking'][$ranking]['ranking'] = $ranking;
        $this->data['CompanyRanking'][$ranking]['company_id'] = $companyId;
        $ranking++;
    }
}