{"id":55,"date":"2021-03-08T00:04:10","date_gmt":"2021-03-08T00:04:10","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=55"},"modified":"2025-04-05T14:02:56","modified_gmt":"2025-04-05T14:02:56","slug":"php-variables","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-variables\/","title":{"rendered":"PHP Variables"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you will learn how to use <strong>PHP variables <\/strong>to store data in programs.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='defining-a-variable'>Defining a variable <a href=\"#defining-a-variable\" class=\"anchor\" id=\"defining-a-variable\" title=\"Anchor for Defining a variable\">#<\/a><\/h2>\n\n\n\n<p>A variable stores a value of any type, e.g., a&nbsp;<a href=\"https:\/\/phptutorial.net\/php-tutorial\/php-string\/\">string<\/a>, a <a href=\"https:\/\/phptutorial.net\/php-tutorial\/php-int\/\">number<\/a>, an&nbsp;<a href=\"https:\/\/phptutorial.net\/php-tutorial\/php-array\/\">array<\/a>, or an&nbsp;<a href=\"https:\/\/phptutorial.net\/php-oop\/php-objects\/\">object<\/a>.<\/p>\n\n\n\n<p>A variable has a name and is associated with a value. To define a variable, you use the following 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\">$variable_name = value;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>When defining a variable, you need to follow these rules:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The variable name must start with the dollar sign (<code>$<\/code>).<\/li>\n\n\n\n<li>The first character after the dollar sign ( <code>$<\/code>) must be a letter (<code>a-z<\/code>) or\u00a0the underscore ( <code>_<\/code> ).<\/li>\n\n\n\n<li>The remaining characters can be underscores, letters, or numbers.<\/li>\n<\/ul>\n\n\n\n<p>PHP variables are case-sensitive. It means that <code>$message<\/code> and <code>$Message<\/code>&nbsp;variables are entirely different.<\/p>\n\n\n\n<p>The following example defines a variable called <code>$title<\/code>:<\/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$title = <span class=\"hljs-string\">\"PHP is awesome!\"<\/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=PD9waHAKCiR0aXRsZSA9ICJQSFAgaXMgYXdlc29tZSEiOw\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>To display the values of variables on a webpage, you&#8217;ll use the <code>echo<\/code> construct. For example:<\/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\">&lt;!DOCTYPE html&gt;\n&lt;html lang=<span class=\"hljs-string\">\"en\"<\/span>&gt;\n&lt;head&gt;\n    &lt;meta charset=<span class=\"hljs-string\">\"UTF-8\"<\/span>&gt;\n    &lt;meta name=<span class=\"hljs-string\">\"viewport\"<\/span> content=<span class=\"hljs-string\">\"width=device-width, initial-scale=1.0\"<\/span>&gt;\n    &lt;title&gt;PHP Variables&lt;\/title&gt;\n&lt;\/head&gt;\n&lt;body&gt;\n    <span class=\"hljs-meta\">&lt;?php<\/span>\n        $title = <span class=\"hljs-string\">'PHP is awesome!'<\/span>;\n    <span class=\"hljs-meta\">?&gt;<\/span>\n    &lt;h1&gt;<span class=\"hljs-meta\">&lt;?php<\/span> <span class=\"hljs-keyword\">echo<\/span> $title; <span class=\"hljs-meta\">?&gt;<\/span>&lt;\/h1&gt;\n&lt;\/body&gt;\n&lt;\/html&gt;<\/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=PD9waHAKCiR0aXRsZSA9ICJQSFAgaXMgYXdlc29tZSEiOwplY2hvICR0aXRsZTs\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>If you open the page, you&#8217;ll see the following message:<\/p>\n\n\n<pre class=\"wp-block-code\"><span><code class=\"hljs\">PHP is awesome!<\/code><\/span><\/pre>\n\n\n<p>Another shorter way to show the value of a variable on a page is to use the following syntax:<\/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;?<\/span>= $variable_name <span class=\"hljs-meta\">?&gt;<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>For example, the following shows the value of the <code>$title<\/code> variable in the heading:<\/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\">&lt;!DOCTYPE html&gt;\n&lt;html lang=<span class=\"hljs-string\">\"en\"<\/span>&gt;\n&lt;head&gt;\n    &lt;meta charset=<span class=\"hljs-string\">\"UTF-8\"<\/span>&gt;\n    &lt;meta name=<span class=\"hljs-string\">\"viewport\"<\/span> content=<span class=\"hljs-string\">\"width=device-width, initial-scale=1.0\"<\/span>&gt;\n    &lt;title&gt;PHP Variables&lt;\/title&gt;\n&lt;\/head&gt;\n&lt;body&gt;\n    <span class=\"hljs-meta\">&lt;?php<\/span>\n\t\t$title = <span class=\"hljs-string\">'PHP is awesome!'<\/span>;\n\t<span class=\"hljs-meta\">?&gt;<\/span>\n    \n    &lt;h1&gt;<span class=\"hljs-meta\">&lt;?<\/span>= $title; <span class=\"hljs-meta\">?&gt;<\/span>&lt;\/h1&gt;\n&lt;\/body&gt;\n&lt;\/html&gt;<\/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=PCFET0NUWVBFIGh0bWw-CjxodG1sIGxhbmc9ImVuIj4KPGhlYWQ-CiAgICA8bWV0YSBjaGFyc2V0PSJVVEYtOCI-CiAgICA8bWV0YSBuYW1lPSJ2aWV3cG9ydCIgY29udGVudD0id2lkdGg9ZGV2aWNlLXdpZHRoLCBpbml0aWFsLXNjYWxlPTEuMCI-CiAgICA8dGl0bGU-UEhQIFZhcmlhYmxlczwvdGl0bGU-CjwvaGVhZD4KPGJvZHk-CiAgICA8P3BocAoJCSR0aXRsZSA9ICdQSFAgaXMgYXdlc29tZSEnOwoJPz4KICAgIAogICAgPGgxPjw_PSAkdGl0bGU7ID8-PC9oMT4KPC9ib2R5Pgo8L2h0bWw-\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Mixing PHP code with HTML will make the code unmaintainable, especially when the application grows. To avoid this, you can separate the code into separate files. For example:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>index.php<\/code> &#8211; store the logic for defining and assigning value to variables.<\/li>\n\n\n\n<li><code>index.view.php<\/code> &#8211; store the code that displays the variables.<\/li>\n\n\n\n<li>Use the <code>require<\/code> construct to include the code from the <code>index.view.php<\/code> in the <code>index.php<\/code> file.<\/li>\n<\/ul>\n\n\n\n<p>The following shows the contents of the <code>index.view.php<\/code> file:<\/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\">&lt;!DOCTYPE html&gt;\n&lt;html lang=<span class=\"hljs-string\">\"en\"<\/span>&gt;\n&lt;head&gt;\n    &lt;meta charset=<span class=\"hljs-string\">\"UTF-8\"<\/span>&gt;\n    &lt;meta name=<span class=\"hljs-string\">\"viewport\"<\/span> content=<span class=\"hljs-string\">\"width=device-width, initial-scale=1.0\"<\/span>&gt;\n    &lt;title&gt;PHP Variables&lt;\/title&gt;\n&lt;\/head&gt;\n&lt;body&gt;\n    &lt;h1&gt;<span class=\"hljs-meta\">&lt;?<\/span>= $title <span class=\"hljs-meta\">?&gt;<\/span>&lt;\/h1&gt;\n&lt;\/body&gt;\n&lt;\/html&gt;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The following shows the contents of the <code>index.php<\/code> file:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$title = <span class=\"hljs-string\">'PHP is awesome!'<\/span>;\n<span class=\"hljs-keyword\">require<\/span> <span class=\"hljs-string\">'index.view.php'<\/span>;<\/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>If you open the <code>index.php<\/code> file on the web browser, you&#8217;ll see the same output.<\/p>\n\n\n\n<p>This separates the code responsible for logic from the code responsible for displaying the file. In programming, this is called the&nbsp;<strong>separation of concerns<\/strong> (SoC).<\/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>A variable stores a value, and its name always starts with <code>$<\/code> sign.<\/li>\n\n\n\n<li>Use the separation of concerns principle to separate the PHP logic from HTML.<\/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=\"55\"\n\t\t\t\tdata-post-url=\"https:\/\/www.phptutorial.net\/php-tutorial\/php-variables\/\"\n\t\t\t\tdata-post-title=\"PHP Variables\"\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=\"55\"\n\t\t\t\tdata-post-url=\"https:\/\/www.phptutorial.net\/php-tutorial\/php-variables\/\"\n\t\t\t\tdata-post-title=\"PHP Variables\"\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 PHP variables to store data in programs.<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":15,"menu_order":4,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-55","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/55","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=55"}],"version-history":[{"count":5,"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/55\/revisions"}],"predecessor-version":[{"id":2939,"href":"https:\/\/www.phptutorial.net\/wp-json\/wp\/v2\/pages\/55\/revisions\/2939"}],"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=55"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}