PHP：str_replace不起作用（SO上的其他答案没有帮助）

Question

我写了以下SSCCE来证明我有一个string（某些HTML），我正在使用simple_html_dom解析器查找具有特定值的div class属性。这很好用。但我需要从父字符串中删除此div。所以我使用str_replace，但它似乎不起作用。请告诉我原因和解决方案是什么。

我检查了解决类似问题的问题的解决方案，但他们没有应用或解决我的问题。我还尝试使用来自this question的答案的str_replace_first。但它也不起作用。

您可以在屏幕截图中看到它只是在打印$haystack后打印整个--------。

$haystack = '<div class="region-content"  style="margin-right:100px; margin-left:100px;">
                                                                                                <div role="main"><span id="maincontent"></span><div class="que description informationitem notyetanswered" id="q6"><h4 class="accesshide">Question text</h4><input type="hidden" name="q3:6_:sequencecheck" value="1" /><div class="qtext"><p style="font-family: HelveticaNeueW01-55Roma, Helvetica, Arial, san-serif; margin: 0px 0px 20px; padding: 0px; color: #464646; font-size: 14.4444446563721px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.5px; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff;">Schools expect textbooks to be a valuable source of information for students. My research suggests, however, that textbooks that address the place of Native Americans within the history of the United States distort history to suit a particular cultural value system. In some textbooks, for example, settlers are pictured as more humane, complex, skillful, and wise than Native Americans. In essence, textbooks stereotype and depreciate the numerous Native American cultures while reinforcing the attitude that the European conquest of the New World denotes the superiority of European cultures. Although textbooks evaluate Native American architecture, political systems, and homemaking, I contend that they do it from an ethnocentric, European perspective without recognizing that other perspectives are possible. </p>
<p style="font-family: HelveticaNeueW01-55Roma, Helvetica, Arial, san-serif; margin: 0px 0px 20px; padding: 0px; color: #464646; font-size: 14.4444446563721px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.5px; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff;">One argument against my contention asserts that, by nature, textbooks are culturally biased and that I am simply underestimating children\'s ability to see through these biases. Some researchers even claim that by the time students are in high school, they know they cannot take textbooks literally. Yet substantial evidence exists to the contrary. Two researchers, for example, have conducted studies that suggest that children\'s attitudes about particular cultures are strongly influenced by the textbooks used in schools. Given this, an ongoing, careful review of how school textbooks depict Native Americans is certainly warranted.</p></div><div class="im-controls"><input type="hidden" name="q3:6_-seen" value="1" /></div></div>

<div class="que multichoice deferredfeedback notyetanswered" id="q7"><div class="qtext"><p><span style="color: #464646; font-family: HelveticaNeueW01-55Roma, Helvetica, Arial, san-serif; font-size: 14.4444446563721px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.5px; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none; background-color: #ffffff;">Which of the following would most logically be the topic of the paragraph immediately following the passage?</span></p></div><div class="ablock"><div class="prompt">Select one:</div><div class="answer"><div class="r0"><input type="radio" name="q3:7_answer" value="0" id="q3:7_answer0" /><label for="q3:7_answer0">a. <span style="color: #464646; font-family: HelveticaNeueW01-55Roma, Helvetica, Arial, san-serif; font-size: 14.4444446563721px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.5px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none; background-color: #ffffff;">the contributions of European immigrants to the development of the United States</span></label> </div>
<div class="r1"><input type="radio" name="q3:7_answer" value="1" id="q3:7_answer1" /><label for="q3:7_answer1">b. <span style="color: #464646; font-family: HelveticaNeueW01-55Roma, Helvetica, Arial, san-serif; font-size: 14.4444446563721px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.5px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none; background-color: #ffffff;"><span class="Apple-converted-space"> </span>the centrality of the teacher\'s role in United States history courses</span></label> </div>
<div class="r0"><input type="radio" name="q3:7_answer" value="2" id="q3:7_answer2" /><label for="q3:7_answer2">c. <span style="color: #464646; font-family: HelveticaNeueW01-55Roma, Helvetica, Arial, san-serif; font-size: 14.4444446563721px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.5px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none; background-color: #ffffff;">nontraditional methods of teaching United States history</span></label> </div>
<div class="r1"><input type="radio" name="q3:7_answer" value="3" id="q3:7_answer3" /><label for="q3:7_answer3">d. <span style="color: #464646; font-family: HelveticaNeueW01-55Roma, Helvetica, Arial, san-serif; font-size: 14.4444446563721px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.5px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none; background-color: #ffffff;">specific ways to evaluate the biases of United States history textbooks <br /></span></label> </div>
<div class="r0"><input type="radio" name="q3:7_answer" value="4" id="q3:7_answer4" /><label for="q3:7_answer4">e. <span style="color: #464646; font-family: HelveticaNeueW01-55Roma, Helvetica, Arial, san-serif; font-size: 14.4444446563721px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.5px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none; background-color: #ffffff;">ways in which parents influence children\'s political attitudes <br /></span></label> </div>
</div></div></div>';

require('C:/xampp/htdocs/simple_html_dom.php');
$html = str_get_html($haystack);
foreach($html->find('div[class=que description informationitem notyetanswered]') as $h) {
    $reading_passage_outertext = $h->outertext;
}
$hay = str_replace($reading_passage_outertext, "", $haystack);
echo $reading_passage_outertext;
echo '---------------------------------------------------------------------------------------------------------------';
echo $hay;

Answer 1

我猜outertext正在返回解析后的html的解释。因此它可能会删除多余的空间，并可能混淆属性的顺序。换句话说，你得到的字符串不同于str_get_html所带来的字符串。你可能只想使用解析器而不是str_replace来删除div

Answer 2

我在你的例子中看到的是，

$hay = str_replace($reading_passage_outertext, "", $haystack);
echo $reading_passage_outertext;

不属于foreach。 所以$ reading_passage_outertext只包含最后一个条目，str_replace不起作用。

我也不确定为什么要浏览str_get_html。 它没有任何意义，并且需要相当高的性能。

str_replace也接受数组作为模式和替换值。 请尝试仅使用str_replace。