PHP将英文数字转换为阿拉伯数字

<?php
function word_digit($word) {
    $warr = explode(&#39;;&#39;,$word);
    $result = &#39;&#39;;
    foreach($warr as $value){
        switch(trim($value)){
            case &#39;zero&#39;:
                $result .= &#39;0&#39;;
                break;
            case &#39;one&#39;:
                $result .= &#39;1&#39;;
                break;
            case &#39;two&#39;:
                $result .= &#39;2&#39;;
                break;
            case &#39;three&#39;:
                $result .= &#39;3&#39;;
                break;
            case &#39;four&#39;:
                $result .= &#39;4&#39;;
                break;
            case &#39;five&#39;:
                $result .= &#39;5&#39;;
                break;
            case &#39;six&#39;:
                $result .= &#39;6&#39;;
                break;
            case &#39;seven&#39;:
                $result .= &#39;7&#39;;
                break;
            case &#39;eight&#39;:
                $result .= &#39;8&#39;;
                break;
            case &#39;nine&#39;:
                $result .= &#39;9&#39;;
                break;
        }
    }
    return $result;
}

echo word_digit("zero;three;five;six;eight;one")."\n";
echo word_digit("seven;zero;one")."\n";

035681                                                                 
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