{"id":2095,"date":"2021-07-01T10:17:57","date_gmt":"2021-07-01T10:17:57","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=2095"},"modified":"2025-04-06T05:06:43","modified_gmt":"2025-04-06T05:06:43","slug":"php-uksort","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-uksort\/","title":{"rendered":"PHP uksort"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you&#8217;ll learn how to use the PHP <code>uksort()<\/code> function to sort an array by keys using a user-defined comparison function.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='introduction-to-the-php-uksort-function'>Introduction to the PHP uksort() function <a href=\"#introduction-to-the-php-uksort-function\" class=\"anchor\" id=\"introduction-to-the-php-uksort-function\" title=\"Anchor for Introduction to the PHP uksort() function\">#<\/a><\/h2>\n\n\n\n<p>The <code>uksort()<\/code> function allows you to sort an array by key using a user-defined comparison function. Typically, you use the <code>uksort()<\/code> function to sort the keys of an <a href=\"https:\/\/phptutorial.net\/php-tutorial\/php-associative-arrays\/\">associative array<\/a>.<\/p>\n\n\n\n<p>The following shows how to use the <code>uksort()<\/code> function&#8217;s syntax:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\">uksort(<span class=\"hljs-keyword\">array<\/span> &amp;$array, callable $callback): bool<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The <code>uksort()<\/code> function has two parameters:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>$array<\/code> is the input array.<\/li>\n\n\n\n<li><code>$callback<\/code> is the comparison function that determines the order of keys.<\/li>\n<\/ul>\n\n\n\n<p>Here&#8217;s the syntax of the callback function:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\">callback(mixed $x, mixed $y): int<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The callback function returns an integer less than, equal to, or greater than zero if <code>$x<\/code> is less than, equal to, or greater than <code>$y<\/code>.<\/p>\n\n\n\n<p>The <code>uksort()<\/code> function returns a boolean value, <code>true<\/code> on success or <code>false<\/code> on failure.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='the-php-uksort-function-example'>The PHP uksort() function example <a href=\"#the-php-uksort-function-example\" class=\"anchor\" id=\"the-php-uksort-function-example\" title=\"Anchor for The PHP uksort() function example\">#<\/a><\/h2>\n\n\n\n<p>The following example shows how to use the <code>uksort()<\/code> function to sort the keys of the <code>$name<\/code> array case-insensitively:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$names = &#91;\n    <span class=\"hljs-string\">'c'<\/span> =&gt; <span class=\"hljs-string\">'Charlie'<\/span>,\n    <span class=\"hljs-string\">'A'<\/span> =&gt; <span class=\"hljs-string\">'Alex'<\/span>,\n    <span class=\"hljs-string\">'b'<\/span> =&gt; <span class=\"hljs-string\">'Bob'<\/span>\n];\n\nuksort(\n    $names, \n    fn ($x, $y) =&gt; strtolower($x) &lt;=&gt; strtolower($y)\n);\n\nprint_r($names);<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><a href=\"https:\/\/phptutorial.net\/playground\/?q=PD9waHAKCiRuYW1lcyA9IFsKICAgICdjJyA9PiAnQ2hhcmxpZScsCiAgICAnQScgPT4gJ0FsZXgnLAogICAgJ2InID0-ICdCb2InCl07Cgp1a3NvcnQoCiAgICAkbmFtZXMsIAogICAgZm4gKCR4LCAkeSkgPT4gc3RydG9sb3dlcigkeCkgPD0-IHN0cnRvbG93ZXIoJHkpCik7CgpwcmludF9yKCRuYW1lcyk7\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-keyword\">Array<\/span>\n(\n    &#91;A] =&gt; Alex\n    &#91;b] =&gt; Bob\n    &#91;c] =&gt; Charlie\n)<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='summary'>Summary <a href=\"#summary\" class=\"anchor\" id=\"summary\" title=\"Anchor for Summary\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Use the <code>uksort()<\/code> function to sort an array by key using a user-defined comparison function.<\/li>\n<\/ul>\n<div class=\"helpful-block-content\" data-title=\"\">\n\t<header>\n\t\t<div class=\"wth-question\">Did you find this tutorial useful?<\/div>\n\t\t<div class=\"wth-thumbs\">\n\t\t\t<button\n\t\t\t\tdata-post=\"2095\"\n\t\t\t\tdata-post-url=\"https:\/\/www.phptutorial.net\/php-tutorial\/php-uksort\/\"\n\t\t\t\tdata-post-title=\"PHP uksort\"\n\t\t\t\tdata-response=\"1\"\n\t\t\t\tclass=\"wth-btn-rounded wth-yes-btn\"\n\t\t\t>\n\t\t\t\t<svg\n\t\t\t\t\txmlns=\"http:\/\/www.w3.org\/2000\/svg\"\n\t\t\t\t\tviewBox=\"0 0 24 24\"\n\t\t\t\t\tfill=\"none\"\n\t\t\t\t\tstroke=\"currentColor\"\n\t\t\t\t\tstroke-width=\"2\"\n\t\t\t\t\tstroke-linecap=\"round\"\n\t\t\t\t\tstroke-linejoin=\"round\"\n\t\t\t\t\tclass=\"feather feather-thumbs-up block w-full h-full\"\n\t\t\t\t>\n\t\t\t\t\t<path\n\t\t\t\t\t\td=\"M14 9V5a3 3 0 0 0-3-3l-4 9v11h11.28a2 2 0 0 0 2-1.7l1.38-9a2 2 0 0 0-2-2.3zM7 22H4a2 2 0 0 1-2-2v-7a2 2 0 0 1 2-2h3\"\n\t\t\t\t\t><\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t<span class=\"sr-only\"> Yes <\/span>\n\t\t\t<\/button>\n\n\t\t\t<button\n\t\t\t\tdata-response=\"0\"\n\t\t\t\tdata-post=\"2095\"\n\t\t\t\tdata-post-url=\"https:\/\/www.phptutorial.net\/php-tutorial\/php-uksort\/\"\n\t\t\t\tdata-post-title=\"PHP uksort\"\n\t\t\t\tclass=\"wth-btn-rounded wth-no-btn\"\n\t\t\t>\n\t\t\t\t<svg\n\t\t\t\t\txmlns=\"http:\/\/www.w3.org\/2000\/svg\"\n\t\t\t\t\tviewBox=\"0 0 24 24\"\n\t\t\t\t\tfill=\"none\"\n\t\t\t\t\tstroke=\"currentColor\"\n\t\t\t\t\tstroke-width=\"2\"\n\t\t\t\t\tstroke-linecap=\"round\"\n\t\t\t\t\tstroke-linejoin=\"round\"\n\t\t\t\t>\n\t\t\t\t\t<path\n\t\t\t\t\t\td=\"M10 15v4a3 3 0 0 0 3 3l4-9V2H5.72a2 2 0 0 0-2 1.7l-1.38 9a2 2 0 0 0 2 2.3zm7-13h2.67A2.31 2.31 0 0 1 22 4v7a2.31 2.31 0 0 1-2.33 2H17\"\n\t\t\t\t\t><\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t<span class=\"sr-only\"> No <\/span>\n\t\t\t<\/button>\n\t\t<\/div>\n\t<\/header>\n\n\t<div class=\"wth-form hidden\">\n\t\t<div class=\"wth-form-wrapper\">\n\t\t\t<div class=\"wth-title\"><\/div>\n\t\t\t\n\t\t\t<textarea class=\"wth-message\"><\/textarea>\n\n\t\t\t<button class=\"btn btn-primary wth-btn-submit\">Send<\/button>\n\t\t\t<button class=\"btn wth-btn-cancel\">Cancel<\/button>\n\t\t\n\t\t<\/div>\n\t<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>In this tutorial, you&#8217;ll learn how to use the PHP uksort() function to sort an array by keys using a user-defined comparison function.<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":15,"menu_order":62,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2095","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/2095","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/comments?post=2095"}],"version-history":[{"count":4,"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/2095\/revisions"}],"predecessor-version":[{"id":3103,"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/2095\/revisions\/3103"}],"up":[{"embeddable":true,"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/15"}],"wp:attachment":[{"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/media?parent=2095"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}