如何在变量中使用'if‘和'else’

Question

在下面的PHP代码中，我试图使用if / far语句来评估返回的字符串是否为空；但是，到目前为止，我还没有成功。

$result = '<div class="card-deck">';

if($rows > 1) {
    while($list = $engrams->fetch_assoc()) {
        $result .= '
        <div class="col-4 p-2">
            <div class="card border-info m-1">
                <img src="/assets/images/items/'.$list['image'].'" alt="'.$list['name'].'" class="card-img-top">
                <div class="card-body" style="margin-left: 60px; position: absolute; text-align: center;">
                    <p class="card-title">'.$list['name'].'</p>
                </div>
                <div class="card-body" style="margin-top: 50px;">
                    <p>'.$list['description'].'</p>
                    <p>'.$list['res_name1'].'</p>
                    <p>'.$list['res_name2'].'</p>
                    <p>'.$list['res_name3'].'</p>
                </div>
                <div class="card-footer d-flex justify-content-between">
                    <small><span class="text-left text-muted">Level Required: '.$list['lvl'].'</span></small>
                    'if (empty($list['engram_points'])) {'<small>PLM</small>'}'
                    'else {'<small><span class="text-right text-muted">Skill Points: '.$list['engram_points'].'</span></small>'}'
                </div>
            </div>
        </div>
        ';
    }
}
$result .= '</div>';

echo json_encode(['result'=>$result,'rows'=>$rows,'qty'=>$qty,'active'=>$active])

Answer 1

如前所述，三元操作符是要走的路。

当与您的if else代码一起使用时，如下所示：

<div class="card-footer d-flex justify-content-between">
    <small>
        <span class="text-left text-muted">Level Required: '.$list['lvl'].'</span> 
    </small>'
    . ( empty($list['engram_points']) ? '<small>PLM</small>' : '<small><span class="text-right text-muted">Skill Points: '.$list['engram_points'].'</span></small>' ) .
'</div>'

Answer 2

以下是其中的诀窍：

        <div class="card-footer d-flex justify-content-between">
            <small><span class="text-left text-muted">Level Required: '.$list['lvl'].'</span></small>
            '.empty($list['engram_points']) ? '<small>PLM</small>' : '<small><span class="text-right text-muted">Skill Points: '.$list['engram_points'].'</span></small>'.'
        </div>

Answer 3

您不能将代码放入这样的字符串中。但是，您可以断开字符串并在循环中使用if/ can .就像这样：

while($list = $engrams->fetch_assoc()) {
        $result .= '
        <div class="col-4 p-2">
            <div class="card border-info m-1">
                <img src="/assets/images/items/'.$list['image'].'" alt="'.$list['name'].'" class="card-img-top">
                <div class="card-body" style="margin-left: 60px; position: absolute; text-align: center;">
                    <p class="card-title">'.$list['name'].'</p>
                </div>
                <div class="card-body" style="margin-top: 50px;">
                    <p>'.$list['description'].'</p>
                    <p>'.$list['res_name1'].'</p>
                    <p>'.$list['res_name2'].'</p>
                    <p>'.$list['res_name3'].'</p>
                </div>
                <div class="card-footer d-flex justify-content-between">
                    <small><span class="text-left text-muted">Level Required: '.$list['lvl'].'</span></small>';

                    if (empty($list['engram_points'])) {
                       $result .= '<small>PLM</small>';
                    }
                    else {
                       $result .= '<small><span class="text-right text-muted">Skill Points: '.$list['engram_points'].'</span></small>;
                    }

        $result .= '        </div>
            </div>
        </div>
        ';
    }