中文(繁體)
中文(繁體)
最常見的錯誤之一是傳遞給$keys參數的值不是數組。例如，傳遞一個字符串或者一個數字：
<span><span><span class="hljs-variable">$keys</span></span><span> = </span><span><span class="hljs-string">'abc'</span></span><span>; </span><span><span class="hljs-comment">// 錯誤：傳遞的是字符串而不是數組</span></span><span>
</span><span><span class="hljs-variable">$value</span></span><span> = </span><span><span class="hljs-number">1</span></span><span>;
</span><span><span class="hljs-variable">$result</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_fill_keys</span></span><span>(</span><span><span class="hljs-variable">$keys</span></span><span>, </span><span><span class="hljs-variable">$value</span></span><span>); </span><span><span class="hljs-comment">// 會觸發警告</span></span><span>
</span></span>解決方法：確保$keys參數是一個有效的數組。如果你不確定類型，可以使用is_array()來檢查：
<span><span><span class="hljs-keyword">if</span></span><span> (!</span><span><span class="hljs-title function_ invoke__">is_array</span></span><span>(</span><span><span class="hljs-variable">$keys</span></span><span>)) {
</span><span><span class="hljs-variable">$keys</span></span><span> = (</span><span><span class="hljs-keyword">array</span></span><span>) </span><span><span class="hljs-variable">$keys</span></span><span>; </span><span><span class="hljs-comment">// 將非數組的值強制轉換為數組</span></span><span>
}
</span><span><span class="hljs-variable">$result</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_fill_keys</span></span><span>(</span><span><span class="hljs-variable">$keys</span></span><span>, </span><span><span class="hljs-variable">$value</span></span><span>);
</span></span>$value參數的類型其實並沒有嚴格要求，但某些情況下，傳遞的值可能會導致意外的結果。例如，傳遞一個對像或資源類型的數據時，可能導致輸出不如預期：
<span><span><span class="hljs-variable">$keys</span></span><span> = [</span><span><span class="hljs-string">'a'</span></span><span>, </span><span><span class="hljs-string">'b'</span></span><span>, </span><span><span class="hljs-string">'c'</span></span><span>];
</span><span><span class="hljs-variable">$value</span></span><span> = </span><span><span class="hljs-title function_ invoke__">fopen</span></span><span>(</span><span><span class="hljs-string">'file.txt'</span></span><span>, </span><span><span class="hljs-string">'r'</span></span><span>); </span><span><span class="hljs-comment">// 錯誤：資源類型的值</span></span><span>
</span><span><span class="hljs-variable">$result</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_fill_keys</span></span><span>(</span><span><span class="hljs-variable">$keys</span></span><span>, </span><span><span class="hljs-variable">$value</span></span><span>);
</span></span>解決方法：確保$value的類型適合用作數組的元素值。對於不可預期的類型，可以通過類型檢查來避免這種情況：
<span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">is_resource</span></span><span>(</span><span><span class="hljs-variable">$value</span></span><span>)) {
</span><span><span class="hljs-variable">$value</span></span><span> = (</span><span><span class="hljs-keyword">string</span></span><span>)</span><span><span class="hljs-variable">$value</span></span><span>; </span><span><span class="hljs-comment">// 轉換資源類型為字符串</span></span><span>
}
</span><span><span class="hljs-variable">$result</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_fill_keys</span></span><span>(</span><span><span class="hljs-variable">$keys</span></span><span>, </span><span><span class="hljs-variable">$value</span></span><span>);
</span></span>雖然array_fill_keys支持任何類型的鍵（包括字符串、整數等），但在某些場景下，混合類型的鍵可能會導致數組的不一致性或難以理解的行為。特別是在使用對像作為鍵名時，可能會因為對象的hash值（即__hash() ）導致鍵不一致。
解決方法：避免使用不可序列化的對像作為鍵名。可以確保數組$keys中的每個元素都能正確轉化為字符串或整數。
<span><span><span class="hljs-variable">$keys</span></span><span> = [</span><span><span class="hljs-keyword">new</span></span><span> </span><span><span class="hljs-built_in">stdClass</span></span><span>(), </span><span><span class="hljs-string">'b'</span></span><span>, </span><span><span class="hljs-string">'c'</span></span><span>]; </span><span><span class="hljs-comment">// 錯誤：對像類型的鍵</span></span><span>
</span><span><span class="hljs-variable">$value</span></span><span> = </span><span><span class="hljs-number">1</span></span><span>;
</span><span><span class="hljs-variable">$result</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_fill_keys</span></span><span>(</span><span><span class="hljs-variable">$keys</span></span><span>, </span><span><span class="hljs-variable">$value</span></span><span>); </span><span><span class="hljs-comment">// 輸出不可預期</span></span><span>
</span></span>最好使用簡單的數據類型作為鍵：
<span><span><span class="hljs-variable">$keys</span></span><span> = [</span><span><span class="hljs-string">'a'</span></span><span>, </span><span><span class="hljs-string">'b'</span></span><span>, </span><span><span class="hljs-string">'c'</span></span><span>]; </span><span><span class="hljs-comment">// 正確：所有鍵為字符串</span></span><span>
</span><span><span class="hljs-variable">$result</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_fill_keys</span></span><span>(</span><span><span class="hljs-variable">$keys</span></span><span>, </span><span><span class="hljs-variable">$value</span></span><span>);
</span></span>如果你遇到array_fill_keys函數報錯或輸出不符合預期的情況，調試是非常重要的步驟。以下是一些調試的建議：
使用var_dump輸出變量：檢查傳入的$keys和$value是否符合預期。
查看錯誤日誌：PHP 的錯誤日誌通常可以幫助你定位參數傳遞問題。
使用debug_backtrace調試函數調用棧：在復雜的應用中，函數調用棧可能有助於你找到函數參數傳遞的具體問題。
