{"id":2557,"date":"2021-09-05T10:06:41","date_gmt":"2021-09-05T10:06:41","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=2557"},"modified":"2025-04-07T13:52:59","modified_gmt":"2025-04-07T13:52:59","slug":"php-empty","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-empty\/","title":{"rendered":"PHP empty"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you&#8217;ll learn how to use the PHP <code>empty()<\/code> construct to check if a variable is empty.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='introduction-to-the-php-empty-construct'>Introduction to the PHP empty() construct <a href=\"#introduction-to-the-php-empty-construct\" class=\"anchor\" id=\"introduction-to-the-php-empty-construct\" title=\"Anchor for Introduction to the PHP empty() construct\">#<\/a><\/h2>\n\n\n\n<p>The <code>empty()<\/code> construct accepts a variable and returns <code>true<\/code> if the <a href=\"https:\/\/phptutorial.net\/php-tutorial\/php-variables\/\">variable<\/a> is empty. Otherwise, it returns <code>false<\/code>.<\/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\"><span class=\"hljs-keyword\">empty<\/span>(mixed $v): bool<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>A variable is empty when if it does not exist or if its value is equal to <code>false<\/code>. In other words, a variable that is not set is empty, or its value equals the following:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>false<\/li>\n\n\n\n<li>integer 0<\/li>\n\n\n\n<li>float 0.0 and -0.0<\/li>\n\n\n\n<li>string &#8220;0&#8221;<\/li>\n\n\n\n<li>empty string &#8221;<\/li>\n\n\n\n<li>An array with no element<\/li>\n\n\n\n<li>null<\/li>\n\n\n\n<li>SimpleXML objects created from empty elements that have no attributes.<\/li>\n<\/ul>\n\n\n\n<p>The <code>empty($v)<\/code> is essentially the same as the following expression that uses the <code><a href=\"https:\/\/phptutorial.net\/php-tutorial\/php-isset\/\">isset()<\/a><\/code> and equality (<code>==<\/code>) operator:<\/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\">!<span class=\"hljs-keyword\">isset<\/span>($v) ||  $v == <span class=\"hljs-keyword\">false<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Like the <code>isset()<\/code> construct, the <code>empty()<\/code> is a language construct, not a <a href=\"https:\/\/phptutorial.net\/php-tutorial\/php-functions\/\">function<\/a>. Therefore, you cannot call it using <a href=\"https:\/\/phptutorial.net\/php-tutorial\/php-variable-functions\/\">variable functions<\/a>.<\/p>\n\n\n\n<p>However, you can work around it by defining a function that uses the <code>empty()<\/code> construct and call that function using variable functions:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n<span class=\"hljs-function\"><span class=\"hljs-keyword\">function<\/span> <span class=\"hljs-title\">not_exist_or_false<\/span><span class=\"hljs-params\">($var)<\/span> : <span class=\"hljs-title\">bool<\/span>\n<\/span>{\n    <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-keyword\">empty<\/span>($var);\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Alternatively, you can use the <a href=\"https:\/\/phptutorial.net\/php-tutorial\/php-arrow-functions\/\">arrow function syntax<\/a> to define a new function that uses the <code>empty()<\/code> construct:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$empty = fn($var) =&gt; <span class=\"hljs-keyword\">empty<\/span>($var);<\/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='php-empty-examples'>PHP empty() examples <a href=\"#php-empty-examples\" class=\"anchor\" id=\"php-empty-examples\" title=\"Anchor for PHP empty() examples\">#<\/a><\/h2>\n\n\n\n<p>The following example returns <code>true<\/code> because the <code>$count<\/code> variable is not declared:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\nvar_dump(<span class=\"hljs-keyword\">empty<\/span>($count));<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><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=PD9waHAKCnZhcl9kdW1wKGVtcHR5KCRjb3VudCkpOw\" 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-6\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\">bool(<span class=\"hljs-keyword\">true<\/span>)<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><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 following example also returns <code>true<\/code> because <code>$count<\/code> is zero, which is considered <code>false<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$count = <span class=\"hljs-number\">0<\/span>;\nvar_dump(<span class=\"hljs-keyword\">empty<\/span>($count));<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-7\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><a href=\"https:\/\/phptutorial.net\/playground\/?q=PD9waHAKCiRjb3VudCA9IDA7CnZhcl9kdW1wKGVtcHR5KCRjb3VudCkpOw\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-8\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\">bool(<span class=\"hljs-keyword\">true<\/span>)<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-8\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>If a variable&#8217;s value is <code>false<\/code>, then the <code>empty()<\/code> returns <code>true<\/code>. The following returns <code>true<\/code> for all the falsy values in the <code>$falsy_values<\/code> array:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-9\" 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$falsy_values = &#91;<span class=\"hljs-keyword\">false<\/span>, <span class=\"hljs-number\">0<\/span>, <span class=\"hljs-number\">0.0<\/span>, <span class=\"hljs-string\">\"0\"<\/span>, <span class=\"hljs-string\">''<\/span>, <span class=\"hljs-keyword\">null<\/span>, &#91;]];\n\n<span class=\"hljs-keyword\">foreach<\/span>($falsy_values <span class=\"hljs-keyword\">as<\/span> $value) {\n    var_dump(<span class=\"hljs-keyword\">empty<\/span>($value));\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-9\"><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=PD9waHAKCiRmYWxzeV92YWx1ZXMgPSBbZmFsc2UsIDAsIDAuMCwgIjAiLCAnJywgbnVsbCwgW11dOwoKZm9yZWFjaCgkZmFsc3lfdmFsdWVzIGFzICR2YWx1ZSkgewogICAgdmFyX2R1bXAoZW1wdHkoJHZhbHVlKSk7Cn0\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='when-to-use-the-php-empty-construct'>When to use the PHP empty() construct <a href=\"#when-to-use-the-php-empty-construct\" class=\"anchor\" id=\"when-to-use-the-php-empty-construct\" title=\"Anchor for When to use the PHP empty() construct\">#<\/a><\/h2>\n\n\n\n<p>In practice, you use the <code>empty()<\/code> construct in the situation where you&#8217;re unsure if a variable exists.<\/p>\n\n\n\n<p>For example, suppose you receive an array <code>$data<\/code> from an external source, e.g., an API call or a database query.<\/p>\n\n\n\n<p>To check if the <code>$data<\/code> array has an element with the key <code>'username'<\/code> and it is not empty, and you may use the following expression:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-10\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-keyword\">isset<\/span>($data&#91;<span class=\"hljs-string\">'username'<\/span>]) &amp;&amp; $data&#91;<span class=\"hljs-string\">'username'<\/span>] !== <span class=\"hljs-string\">''<\/span>)<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-10\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>However, it&#8217;s shorter if you use the <code>empty()<\/code> construct:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-11\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\">!<span class=\"hljs-keyword\">empty<\/span>($data&#91;<span class=\"hljs-string\">'username'<\/span>])<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-11\"><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 PHP <code>empty()<\/code> construct to check if a variable is not set or its value is <code>false<\/code>.<\/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=\"2557\"\n\t\t\t\tdata-post-url=\"https:\/\/www.phptutorial.net\/php-tutorial\/php-empty\/\"\n\t\t\t\tdata-post-title=\"PHP empty\"\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 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