php explode <ul> <li>并仅选择带有类的标签

Question

我的字段包含列表<ul class = "..."> <li> <something class = "MY CLASS">。我需要过滤结果，以便只有具有所需类的元素保留在列表中。我试过explode ('<li>', $array);但是我总是返回“原始”列表。我只需要class=" cf_sel_opt"的元素（在第一个列表<a>标记中，在其他<label>标记中）。 我做错了什么？

这是我的PHP代码

foreach ($filters_render_array['html'] as $key => $value) {
    if (strpos($key, 'custom_f_') !== false) {
        $search_class = "cf_sel_opt";
        print_r($value);
    }
}

返回此列表

<ul class="cf_filters_list cf_colorbtn_list" id="cf_list_custom_f_35_129">
    <li>
        <a href="#" class="cf_option  cf_color_btn cf_sel_opt">
            <span class="cf_color_inner" style="background-color:black; width:100%;">
            </span>
        </a>
        <input name="custom_f_35[]" value="313038" type="hidden">
    </li>
    <li>
        <a href="#" class="cf_option  cf_color_btn">
            <span class="cf_color_inner" style="background-color:pink; width:100%;">
            </span>
        </a>
    </li>
    <li>
        <a href="#" class="cf_option  cf_color_btn">
            <span class="cf_color_inner" style="background-color:white; width:100%;">
            </span>
        </a>
    </li>
</ul>
<ul class="cf_filters_list" id="cf_list_custom_f_36_129">
    <li>
        <label class="" for="custom_f_36_129_elid3139">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3139" value="3139" type="checkbox">
            <a href="#">
                7
            </a>
        </label>
    </li>
    <li>
        <label class="" for="custom_f_36_129_elid3231">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3231" value="3231" type="checkbox">
            <a href="#">
                6
            </a>
        </label>
    </li>
    <li>
        <label class="" for="custom_f_36_129_elid3232">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3232" value="3232" type="checkbox">
            <a href="#">
                5
            </a>
        </label>
    </li>
    <li>
        <label class="" for="custom_f_36_129_elid3233">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3233" value="3233" type="checkbox">
            <a href="#">
                4
            </a>
        </label>
    </li>
    <li>
        <label class="" for="custom_f_36_129_elid3334">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3334" value="3334" type="checkbox">
            <a href="#">
                3
            </a>
        </label>
    </li>
    <li>
        <label class="" for="custom_f_36_129_elid3336">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3336" value="3336" type="checkbox">
            <a href="#">
                2
            </a>
        </label>
    </li>
    <li>
        <label class="" for="custom_f_36_129_elid3338">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3338" value="3338" type="checkbox">
            <a href="#">
                2A
            </a>
        </label>
    </li>
    <li>
        <label class=" cf_sel_opt" for="custom_f_36_129_elid3439">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3439" value="3439" checked="checked" type="checkbox">
            <a href="#">
                1
            </a>
        </label>
    </li>
    <li>
        <label class=" cf_sel_opt" for="custom_f_36_129_elid3535">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3535" value="3535" checked="checked" type="checkbox">
            <a href="#">
                00
            </a>
        </label>
    </li>
    <li>
        <label class=" cf_sel_opt" for="custom_f_36_129_elid3633">
            <input name="custom_f_36[]" class="cf_flt" id="custom_f_36_129_elid3633" value="3633" checked="checked" type="checkbox">
            <a href="#">
                0
            </a>
        </label>
    </li>
</ul>
<ul class="cf_filters_list" id="cf_list_custom_f_39_129">
    <li>
        <label class=" cf_sel_opt" for="custom_f_39_129_elid323332">
            <input name="custom_f_39[]" class="cf_flt" id="custom_f_39_129_elid323332" value="323332" checked="checked" type="checkbox">
            <a href="#">
                Light/Mesh lycra
            </a>
        </label>
    </li>
</ul>