http_build_query 函数的基础语法是什么？如何快速掌握它的使用示例？

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<span class="hljs-comment">/**
 * [http_build_query 函数的基础语法是什么？如何快速掌握它的使用示例？]
 *
 * http_build_query 是 PHP 中一个非常实用的函数，主要用于将数组或对象转换为 URL 查询字符串。
 * 它经常用于生成 GET 请求的参数，或者在 API 请求中快速构建查询字符串。
 *
 * 基础语法：
 *
 * string http_build_query(array $data, string $numeric_prefix = "", string $arg_separator = "&amp;", int $encoding_type = PHP_QUERY_RFC1738)
 *
 * 参数说明：
 * 1. $data：必填，数组或对象，需要被转换的键值对。
 * 2. $numeric_prefix：可选，如果数组索引是数字，可以为其加前缀。
 * 3. $arg_separator：可选，参数之间的分隔符，默认为 &amp;。
 * 4. $encoding_type：可选，编码类型，PHP_QUERY_RFC1738 或 PHP_QUERY_RFC3986。
 *
 * 基本使用示例：
 */</span>

</span><span><span class="hljs-comment">// 示例 1：最简单的数组转换</span></span><span>
</span><span><span class="hljs-variable">$params</span></span><span> = [
    </span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Alice'</span></span><span>,
    </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">25</span></span><span>,
    </span><span><span class="hljs-string">'city'</span></span><span> =&gt; </span><span><span class="hljs-string">'Beijing'</span></span><span>
];

</span><span><span class="hljs-variable">$queryString</span></span><span> = </span><span><span class="hljs-title function_ invoke__">http_build_query</span></span><span>(</span><span><span class="hljs-variable">$params</span></span><span>);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-variable">$queryString</span></span><span>;
</span><span><span class="hljs-comment">// 输出：name=Alice&amp;age=25&amp;city=Beijing</span></span><span>

</span><span><span class="hljs-comment">// 示例 2：带数字索引的数组</span></span><span>
</span><span><span class="hljs-variable">$numbers</span></span><span> = [</span><span><span class="hljs-number">10</span></span><span>, </span><span><span class="hljs-number">20</span></span><span>, </span><span><span class="hljs-number">30</span></span><span>];
</span><span><span class="hljs-variable">$queryString2</span></span><span> = </span><span><span class="hljs-title function_ invoke__">http_build_query</span></span><span>(</span><span><span class="hljs-variable">$numbers</span></span><span>, </span><span><span class="hljs-string">'num_'</span></span><span>);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"\n"</span></span><span> . </span><span><span class="hljs-variable">$queryString2</span></span><span>;
</span><span><span class="hljs-comment">// 输出：num_0=10&amp;num_1=20&amp;num_2=30</span></span><span>

</span><span><span class="hljs-comment">// 示例 3：指定参数分隔符</span></span><span>
</span><span><span class="hljs-variable">$queryString3</span></span><span> = </span><span><span class="hljs-title function_ invoke__">http_build_query</span></span><span>(</span><span><span class="hljs-variable">$params</span></span><span>, </span><span><span class="hljs-string">''</span></span><span>, </span><span><span class="hljs-string">';'</span></span><span>);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"\n"</span></span><span> . </span><span><span class="hljs-variable">$queryString3</span></span><span>;
</span><span><span class="hljs-comment">// 输出：name=Alice;age=25;city=Beijing</span></span><span>

</span><span><span class="hljs-comment">// 示例 4：使用 RFC3986 编码</span></span><span>
</span><span><span class="hljs-variable">$queryString4</span></span><span> = </span><span><span class="hljs-title function_ invoke__">http_build_query</span></span><span>(</span><span><span class="hljs-variable">$params</span></span><span>, </span><span><span class="hljs-string">''</span></span><span>, </span><span><span class="hljs-string">'&amp;'</span></span><span>, PHP_QUERY_RFC3986);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"\n"</span></span><span> . </span><span><span class="hljs-variable">$queryString4</span></span><span>;
</span><span><span class="hljs-comment">// 输出：name=Alice&amp;age=25&amp;city=Beijing （空格和特殊字符会被百分号编码）</span></span><span>

<span class="hljs-comment">/**
 * 快速掌握方法：
 * 1. 先记住最基本的数组到字符串的转换方式。
 * 2. 理解 numeric_prefix 对数字索引数组的作用。
 * 3. 熟悉 arg_separator 用于分隔参数。
 * 4. 注意不同编码类型对 URL 安全性的影响。
 *
 * 总结：
 * http_build_query 可以让你快速将数组数据变成可用的 URL 查询字符串，结合 GET 请求或者 API 调用非常方便。
 */</span>
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