{"id":1130,"date":"2021-04-14T08:19:33","date_gmt":"2021-04-14T08:19:33","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=1130"},"modified":"2025-04-06T13:05:23","modified_gmt":"2025-04-06T13:05:23","slug":"php-filter_var","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-filter_var\/","title":{"rendered":"PHP filter_var Function"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you will learn how to use the PHP <code>filter_var()<\/code> function to sanitize and validate data.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='introduction-to-the-php-filter_var-function'>Introduction to the PHP filter_var() function <a href=\"#introduction-to-the-php-filter_var-function\" class=\"anchor\" id=\"introduction-to-the-php-filter_var-function\" title=\"Anchor for Introduction to the PHP filter_var() function\">#<\/a><\/h2>\n\n\n\n<p>The <code>filter_var()<\/code> function allows you to filter a variable using a validation or sanitization filters.<\/p>\n\n\n\n<p>Here&#8217;s the syntax of the <code>filter_var()<\/code> function:<\/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\">filter_var ( mixed $value , int $filter = FILTER_DEFAULT , <span class=\"hljs-keyword\">array<\/span>|int $options = <span class=\"hljs-number\">0<\/span> ) : mixed<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The <code>filter_var()<\/code> function has three parameters:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>$value<\/code> is the value you want to validate or sanitize.<\/li>\n\n\n\n<li><code>$filter<\/code> is the filter id to apply. The filter id determines how the function will filter the <code>$value<\/code>.<\/li>\n\n\n\n<li><code>$options<\/code> is an associative array of filter options or a list of flags separated by the pipe character (<code>|<\/code>).<\/li>\n<\/ul>\n\n\n\n<p>The <code>filter()<\/code> function returns the filtered value, or <code>false<\/code> if fails<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='validating-data'>Validating data <a href=\"#validating-data\" class=\"anchor\" id=\"validating-data\" title=\"Anchor for Validating data\">#<\/a><\/h2>\n\n\n\n<p>The following example uses the filter_var function to validate data:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"HTML, XML\" data-shcb-language-slug=\"xml\"><span><code class=\"hljs language-xml\"><span class=\"php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$id = <span class=\"hljs-string\">'100'<\/span>;\n\n$result = filter_var($id, FILTER_VALIDATE_INT);\n<span class=\"hljs-keyword\">echo<\/span> $result === <span class=\"hljs-keyword\">false<\/span> ? <span class=\"hljs-string\">\"Invalid ID\"<\/span> : <span class=\"hljs-string\">\"Valid ID: $result\"<\/span>;<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">HTML, XML<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">xml<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><a href=\"https:\/\/phptutorial.net\/playground\/?q=PD9waHAKCiRpZCA9ICcxMDAnOwoKJHJlc3VsdCA9IGZpbHRlcl92YXIoJGlkLCBGSUxURVJfVkFMSURBVEVfSU5UKTsKZWNobyAkcmVzdWx0ID09PSBmYWxzZSA_ICJJbnZhbGlkIElEIiA6ICJWYWxpZCBJRDogJHJlc3VsdCI7\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\"><span><code class=\"hljs\">Valid ID: 100<\/code><\/span><\/pre>\n\n\n<p>How it works.<\/p>\n\n\n\n<p>First, declare a variable <code>$id<\/code> with the initial value <code>'100'<\/code>:<\/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\">$id = <span class=\"hljs-string\">'100'<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In practice, the <code>$id <\/code> may come from the query string or external API.<\/p>\n\n\n\n<p>Second, check if<code>$id<\/code> is an interger using the filter id <a href=\"https:\/\/www.php.net\/manual\/en\/filter.constants.php#constant.filter-validate-int\" target=\"_blank\" rel=\"noreferrer noopener\">FILTER_VALIDATE_INT<\/a>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\">$result = filter_var($id, FILTER_VALIDATE_INT);<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The <code>FILTER_VALIDATE_INT<\/code> validates if <code>$id<\/code> is an integer. In this example, the value of the <code>$id<\/code> is a string <code>'100'<\/code>, the function converts it to an integer <code>100<\/code>.<\/p>\n\n\n\n<p>Third, change the value of the <code>$id<\/code> to <code>'abc'<\/code>, the <code>filter_var()<\/code> function will return <code>false<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"HTML, XML\" data-shcb-language-slug=\"xml\"><span><code class=\"hljs language-xml\"><span class=\"php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$id = <span class=\"hljs-string\">'abc'<\/span>;\n\n$result = filter_var($id, FILTER_VALIDATE_INT);\n<span class=\"hljs-keyword\">echo<\/span> $result === <span class=\"hljs-keyword\">false<\/span> ? <span class=\"hljs-string\">\"Invalid ID\"<\/span> : <span class=\"hljs-string\">\"Valid ID: $result\"<\/span>;<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">HTML, XML<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">xml<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><a href=\"https:\/\/phptutorial.net\/playground\/?q=PD9waHAKCiRpZCA9ICdhYmMnOwoKJHJlc3VsdCA9IGZpbHRlcl92YXIoJGlkLCBGSUxURVJfVkFMSURBVEVfSU5UKTsKZWNobyAkcmVzdWx0ID09PSBmYWxzZSA_ICJJbnZhbGlkIElEIiA6ICJWYWxpZCBJRDogJHJlc3VsdCI7\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\"><span><code class=\"hljs\">Invalid ID<\/code><\/span><\/pre>\n\n\n<p>The following example uses the <code>filter_var<\/code> function to check if id is an integer and in the range of 1 and 100:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-6\" data-shcb-language-name=\"HTML, XML\" data-shcb-language-slug=\"xml\"><span><code class=\"hljs language-xml\"><span class=\"php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$id = <span class=\"hljs-number\">120<\/span>;\n\n$result = filter_var($id, FILTER_VALIDATE_INT, &#91;\n    <span class=\"hljs-string\">'options'<\/span> =&gt; &#91;\n        <span class=\"hljs-string\">'min_range'<\/span> =&gt; <span class=\"hljs-number\">1<\/span>,\n        <span class=\"hljs-string\">'max_range'<\/span> =&gt; <span class=\"hljs-number\">100<\/span>,\n    ]\n]);\n\n<span class=\"hljs-keyword\">echo<\/span> $result === <span class=\"hljs-keyword\">false<\/span> ? <span class=\"hljs-string\">\"Invalid ID\"<\/span> : <span class=\"hljs-string\">\"Valid ID: $result\"<\/span>;<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">HTML, XML<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">xml<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><a href=\"https:\/\/phptutorial.net\/playground\/?q=PD9waHAKCiRpZCA9IDEyMDsKCiRyZXN1bHQgPSBmaWx0ZXJfdmFyKCRpZCwgRklMVEVSX1ZBTElEQVRFX0lOVCwgWwogICAgJ29wdGlvbnMnID0-IFsKICAgICAgICAnbWluX3JhbmdlJyA9PiAxLAogICAgICAgICdtYXhfcmFuZ2UnID0-IDEwMCwKICAgIF0KXSk7CgplY2hvICRyZXN1bHQgPT09IGZhbHNlID8gIkludmFsaWQgSUQiIDogIlZhbGlkIElEOiAkcmVzdWx0Ijs\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\"><span><code class=\"hljs\">Invalid ID<\/code><\/span><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='sanitizing-data'>Sanitizing data <a href=\"#sanitizing-data\" class=\"anchor\" id=\"sanitizing-data\" title=\"Anchor for Sanitizing data\">#<\/a><\/h2>\n\n\n\n<p>The following example uses the <code>filter_var()<\/code> function to sanitize a number:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$id = <span class=\"hljs-string\">'120abc'<\/span>;\n$result = filter_var($id, FILTER_SANITIZE_NUMBER_INT);\n\n<span class=\"hljs-keyword\">echo<\/span> $result === <span class=\"hljs-keyword\">false<\/span> ? <span class=\"hljs-string\">\"Invalid ID\"<\/span> : <span class=\"hljs-string\">\"Valid ID: $result\"<\/span>;\n<\/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=PD9waHAKCiRpZCA9ICcxMjBhYmMnOwokcmVzdWx0ID0gZmlsdGVyX3ZhcigkaWQsIEZJTFRFUl9TQU5JVElaRV9OVU1CRVJfSU5UKTsKCmVjaG8gJHJlc3VsdCA9PT0gZmFsc2UgPyAiSW52YWxpZCBJRCIgOiAiVmFsaWQgSUQ6ICRyZXN1bHQiOw\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\"><span><code class=\"hljs\">Valid ID: 120<\/code><\/span><\/pre>\n\n\n<p>The <code>filter_var()<\/code> function with the <code>FILTER_SANITIZE_NUMBER_INT<\/code> filters will remove all characters except the digits, plus, and minus signs from the <code>id<\/code> variable.<\/p>\n\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>filter_var()<\/code> function to validate or sanitize a variable.<\/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=\"1130\"\n\t\t\t\tdata-post-url=\"https:\/\/www.phptutorial.net\/php-tutorial\/php-filter_var\/\"\n\t\t\t\tdata-post-title=\"PHP filter_var Function\"\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=\"1130\"\n\t\t\t\tdata-post-url=\"https:\/\/www.phptutorial.net\/php-tutorial\/php-filter_var\/\"\n\t\t\t\tdata-post-title=\"PHP filter_var Function\"\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 will learn how to use the PHP filter_var() function to sanitize and validate data.<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":15,"menu_order":84,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1130","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/1130","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=1130"}],"version-history":[{"count":4,"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/1130\/revisions"}],"predecessor-version":[{"id":3175,"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/1130\/revisions\/3175"}],"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=1130"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}