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php if statement


The if construct is one of the most important features of many languages, PHP included. It allows for conditional execution of code fragments. PHP features an if structure that is similar to that of C:


	      	if (   expression  ) { 
			  // Run this code 
			} 
			// More code here 
	      

As described in the section about expressions, expression is evaluated to its Boolean value. If expression evaluates to TRUE, PHP will execute statement, and if it evaluates to FALSE - it'll ignore it. More information about what values evaluate to FALSE can be found in the 'Converting to boolean' section.


	      	<?php
			if ($a > $b)
			  echo "a is bigger than b";
			?>
	      

If you only have one statement of code to execute, you can do without the braces entirely. It's a readability issue.


	      	<?php
			if ($a > $b) {
			  echo "a is bigger than b";
			  $b = $a;
			}
			?>
	      


	      	<?php 
				if( $a == 1 || $a == 2 ) { 
				    if( $b == 3 || $b == 4 ) { 
				        if( $c == 5 || $ d == 6 ) { 
				             //Do something here. 
				        } 
				    } 
				} 
				?> 
	      

Note for if statement


If the expression inside the parentheses evaluates to true, the code between the braces is run.


If the expression evaluates to false, the code between the braces is skipped.


example


		  	<?php
		        $Age = 20;
		        if ($Age < 18) {
		                print "under 18\n";
		        } else {
		                print "You're not under 18\n";
		        }
		    ?>
		  

Example - if statement with more conditions


Here's another example that uses the >= (greater than or equal) and <= (less than or equal) comparison operators, as well as the && (and) logical operator:


		  	<?php
			     $myValue = 23; 

			     if ( $myValue  >= 10  &&  $myValue  <= 20 ) { 
			       echo "between 10 and 20."; 
			     }   
			?>
		  

Example nested if


		  	<?php
			     $myValue = 23; 
			     if ( $myValue  >= 10 ) { 
			       if ( $myValue  <= 20 ) { 
			         echo "10 and 20."; 
			       } 
			     }   
			?>
		  



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