Php 尝试组合两个阵列不会'；行不通

我正在尝试将两个选择框合并为一个。代码如下：

//Selectbox 1
<?php $aCities = City::newInstance()->listAll(); ?>
<?php if(count($aCities) > 0 ) { ?>
    <select id="dropdowncities">
        <option value=""><?php _e('Select your location...')?></option>
        <?php foreach($aCities as $city) { ?>
            <option value="<?php echo $city['s_name'] ; ?>"><?php echo $city['s_name'] ; ?>
            </option>
        <?php } ?>
    </select>
<?php } ?>


//Selectbox 2
<?php $aRegions = Region::newInstance()->listAll(); ?>
<?php if(count($aRegions) > 0 ) { ?>
    <select id="dropdownregions">
        <option value=""><?php _e('Select your Region...')?></option>
        <?php foreach($aRegions as $region) { ?>
            <option value="<?php echo $region['s_name'] ; ?>"></option>
        <?php } ?>
    </select>
<?php } ?>

//选择框1
//选择框2
“我做错了什么？”-您似乎在开发时没有启用正确的PHP错误报告功能-否则，应该会给您一个错误。因此，现在请首先启用它。旁注：如果有多行使用PHP，则没有理由在每行上打开和关闭PHP（使用
）。这只会使代码更难阅读。@Nick question编辑了它的数组\u combine not array\u shift你说的“它的数组\u combine not array\u shift”是什么意思？发布的代码不是你真实代码的复制/粘贴吗？如果没有，请复制/粘贴您的实际代码，因为重写可能包含实际代码没有的其他问题，反之亦然。@04FS您是对的。我收到这样的消息：“PHP警告：array_combine（）：两个参数的元素数应该相等”我现在正在更新这个问题
//Combine two select boxes
<?php $aRegions = Region::newInstance()->listAll(); ?>
<?php $aCities = City::newInstance()->listAll(); ?>
<?php $cityandregion = array_combine($aRegions, $aCities); ?>
<?php if(count($aCities) > 0 ) { ?>
    <select id="dropdowncitiesregions">
        <option value=""><?php _e('Select your city and region...')?></option>
        <?php foreach($cityandregion as $city=>$region) { ?>
            <option value="<?php echo $city['s_name'] ; ?><?php echo $region['s_name'] ; ?>"><?php echo $cityandregion['s_name'] ; ?></option>
        <?php } ?>
    </select>
<?php } ?>

<?php
    $cityandregion = array(
        "cities" => Region::newInstance()->listAll(),
        "regions" => City::newInstance()->listAll()
    ); 
    if(count($cityandregion["cities"]) > 0 && count($cityandregion["regions"])) {
        // Regions..
        $html = "<select id=\"dropdownregions\">";
        $html .= "<option value=\"\">('Select your region...')</option>";
        foreach($cityandregion["regions"] as $k => $region) {
            $html .= "<option value=\"" . $region['s_name'] . "\">" . $region['s_name'] . "</option>";
        }
        $html .= "</select></ br>";

        // Cities..
        $html = "<select id=\"dropdowncities\">";
        $html .= "<option value=\"\">('Select your city...')</option>";
        foreach($cityandregion["cities"] as $k => $city) {
            $html .= "<option value=\"" . $city['s_name'] . "\">" . $city['s_name'] . "</option>";
        }
        $html .= "</select></ br>";

        echo $html;
    }
?>