简体中文
简体中文
最常见的错误之一是传递给 $keys 参数的值不是数组。例如，传递一个字符串或者一个数字：
<span><span><span class="hljs-variable">$keys</span></span><span> = </span><span><span class="hljs-string">'abc'</span></span><span>; </span><span><span class="hljs-comment">// 错误：传递的是字符串而不是数组</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">// 会触发警告</span></span><span>
</span></span>解决方法：确保 $keys 参数是一个有效的数组。如果你不确定类型，可以使用 is_array() 来检查：
<span><span><span class="hljs-keyword">if</span></span><span> (!</span><span><span class="hljs-title function_ invoke__">is_array</span></span><span>(</span><span><span class="hljs-variable">$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">// 将非数组的值强制转换为数组</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 参数的类型其实并没有严格要求，但某些情况下，传递的值可能会导致意外的结果。例如，传递一个对象或资源类型的数据时，可能导致输出不如预期：
<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">// 错误：资源类型的值</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>解决方法：确保 $value 的类型适合用作数组的元素值。对于不可预期的类型，可以通过类型检查来避免这种情况：
<span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">is_resource</span></span><span>(</span><span><span class="hljs-variable">$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">// 转换资源类型为字符串</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>虽然 array_fill_keys 支持任何类型的键（包括字符串、整数等），但在某些场景下，混合类型的键可能会导致数组的不一致性或难以理解的行为。特别是在使用对象作为键名时，可能会因为对象的 hash 值（即 __hash()）导致键不一致。
解决方法：避免使用不可序列化的对象作为键名。可以确保数组 $keys 中的每个元素都能正确转化为字符串或整数。
<span><span><span class="hljs-variable">$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">// 错误：对象类型的键</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">// 输出不可预期</span></span><span>
</span></span>最好使用简单的数据类型作为键：
<span><span><span class="hljs-variable">$keys</span></span><span> = [</span><span><span class="hljs-string">'a'</span></span><span>, </span><span><span class="hljs-string">'b'</span></span><span>, </span><span><span class="hljs-string">'c'</span></span><span>]; </span><span><span class="hljs-comment">// 正确：所有键为字符串</span></span><span>
</span><span><span class="hljs-variable">$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 函数报错或输出不符合预期的情况，调试是非常重要的步骤。以下是一些调试的建议：
使用 var_dump 输出变量：检查传入的 $keys 和 $value 是否符合预期。
查看错误日志：PHP 的错误日志通常可以帮助你定位参数传递问题。
使用 debug_backtrace 调试函数调用栈：在复杂的应用中，函数调用栈可能有助于你找到函数参数传递的具体问题。
