{"id":213,"date":"2021-03-08T16:14:18","date_gmt":"2021-03-08T16:14:18","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=213"},"modified":"2025-04-06T01:36:27","modified_gmt":"2025-04-06T01:36:27","slug":"php-if","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-if\/","title":{"rendered":"PHP if"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn about the PHP if statement and how to use it to execute a code block conditionally.<\/p>\n\n\n\n

Introduction to the PHP if statement #<\/a><\/h2>\n\n\n\n

The if<\/code> statement allows you to execute a statement if an expression evaluates to true<\/code>. The following shows the syntax of the if<\/code> statement:<\/p>\n\n\n

<?php<\/span>\n\nif<\/span> ( expression ) \n    statement;<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this syntax, PHP evaluates the expression<\/code> first. If the expression<\/code> evaluates to true<\/code>, PHP executes the statement<\/code>. In case the expression evaluates to false<\/code>, PHP ignores the statement<\/code>.<\/p>\n\n\n\n
The following flowchart illustrates how the if<\/code> statement works:<\/p>\n\n\n
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\"PHP<\/figure>\n<\/div>\n\n\n
The following example uses the if<\/code> statement to display a message if the $is_admin<\/code> variable sets to true<\/code>:<\/p>\n\n\n
<?php<\/span>\n\n$is_admin = true<\/span>;\nif<\/span> ($is_admin)\n    echo<\/span> 'Welcome, admin!'<\/span>;<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Since $is_admin<\/code> is true<\/code>, the script outputs the following message:<\/p>\n\n\n
Welcome, admin!<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Curly braces #<\/a><\/h2>\n\n\n\n
If you want to execute multiple statements in the if<\/code> block, you can use curly braces to group multiple statements like this:<\/p>\n\n\n
<?php<\/span>\n\nif<\/span> ( expression ) {\n   statement1;\n   statement2;\n   \/\/ more statement<\/span>\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The following example uses the if<\/code> statement that executes multiple statements:<\/p>\n\n\n
<?php<\/span>\n\n$can_edit = false<\/span>;\n$is_admin = true<\/span>;\n\nif<\/span> ( $is_admin ) {\n   echo<\/span> 'Welcome, admin!'<\/span>;\n   $can_edit = true<\/span>;\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, the if<\/code> statement displays a message and sets the $can_edit<\/code> variable to true<\/code> if the $is_admin<\/code> variable is true<\/code>.<\/p>\n\n\n\n
It’s a good practice to always use curly braces with the if<\/code> statement even though it has a single statement to execute like this:<\/p>\n\n\n
<?php<\/span>\n\nif<\/span> ( expression ) {\n   statement;\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In addition, you can use spaces between the expression and curly braces to make the code more readable.<\/p>\n\n\n\n
Nesting if statements #<\/a><\/h2>\n\n\n\n
It’s possible to nest an if<\/code> statement inside another if<\/code> statement as follows:<\/p>\n\n\n
<?php<\/span>\n\nif<\/span> ( expression1 ) {\n    \/\/ do something<\/span>\n    if<\/span>( expression2 ) {\n        \/\/ do other things<\/span>\n    }\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The following example shows how to nest an if<\/code> statement in another if<\/code> statement:<\/p>\n\n\n
<?php<\/span>\n\n$is_admin = true<\/span>;\n$can_approve = true<\/span>;\n\nif<\/span> ($is_admin) {\n\techo<\/span> 'Welcome, admin!'<\/span>;\n\tif<\/span> ($can_approve) {\n\t\techo<\/span> 'Please approve the pending items'<\/span>;\n\t}\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Embed if statement in HTML #<\/a><\/h2>\n\n\n\n
To embed an if<\/code> statement in an HTML document, you can use the above syntax. However, PHP provides a better syntax that allows you to mix the if statement with HTML nicely:<\/p>\n\n\n
<?php<\/span> if<\/span> ( expession) : ?><\/span>\n<!-- HTML code here -->\n<?php<\/span> endif<\/span>; ?><\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The following example uses the if<\/code> statement that shows the edit link if the $is_admin<\/code> is true<\/code>:<\/p>\n\n\n
<!DOCTYPE html>\n<html lang=\"en\"<\/span>>\n<head>\n  <meta charset=\"UTF-8\"<\/span>>\n  <title>PHP if<\/span> Statement Demo<\/title>\n<\/head>\n<body>\n  <?php<\/span> $is_admin = true<\/span>; ?><\/span>\n  <?php<\/span> if<\/span> ( $is_admin ) : ?><\/span>\n  <a href=\"#\"<\/span>>Edit<\/a>\n  <?php<\/span> endif<\/span>; ?><\/span>\n  <a href=\"#\"<\/span>>View<\/a> \n<\/body>\n<\/html><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Since the $is_admin<\/code> is true<\/code>, the script shows the Edit link. If you change the value of the $is_admin<\/code> to false<\/code>, you won’t see the Edit link in the output.<\/p>\n\n\n\n
A common mistake with the PHP if statement #<\/a><\/h2>\n\n\n\n
A common mistake that you may make is to use the wrong operator in the if<\/code> statement. For example:<\/p>\n\n\n
<?php<\/span>\n\n$checked = 'on'<\/span>;\nif<\/span>( $checked = 'off'<\/span> ) {\n   echo<\/span> 'The checkbox has not been checked'<\/span>;\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
This script shows a message if the $checked<\/code> is 'off'<\/code>. However, the expression in the if<\/code> statement is an assignment, not a comparison:<\/p>\n\n\n
$checked = 'off'<\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
This expression assigns the literal string 'off'<\/code> to the $checked<\/code> variable and returns that variable. It doesn’t compare the value of the $checked<\/code> variable with the 'off'<\/code> value. Therefore, the expression always evaluates to true<\/code>, which is not correct.<\/p>\n\n\n\n
To avoid this error, you can place the value first before the comparison operator and the variable after the comparison operator like this:<\/p>\n\n\n
<?php<\/span>\n\n$checked = 'on'<\/span>;\nif<\/span>('off'<\/span> == $checked ) {\n   echo<\/span> 'The checkbox has not been checked'<\/span>;\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
If you accidentally use the assignment operator (=), PHP will raise a syntax error instead:<\/p>\n\n\n
<?php<\/span>\n\n$checked = 'on'<\/span>;\nif<\/span> ('off'<\/span> = $checked) {\n\techo<\/span> 'The checkbox has not been checked'<\/span>;\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Error:<\/p>\n\n\n
Parse error: syntax error, unexpected '='<\/span> ...<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
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  • The if<\/code> statement executes a statement if<\/code> a condition evaluates to true<\/code>.<\/li>\n\n\n\n
  • Always use curly braces even if you have a single statement to execute in the if<\/code> statement. It makes the code more obvious.<\/li>\n\n\n\n
  • Use the pattern if ( value == $variable_name ) {}<\/code> to avoid possible mistakes.<\/li>\n<\/ul>\n
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