PHP if statement syntax

Posted December 27, 2003 by Quinn McHenry in PHP programming

Last Updated on

Examples of using the “if” command in PHP.

The simplest if statement executes command(s) if a condition evaluates as true:

if ($var > 0 ) {
// code here run if $var is positive
echo "Square root is: ".sqrt($var);
}

An optional else block can be added to execute code if the test condition evaluates as false. Multiple lines of code must be enclosed within { braces } while a single statement can be used in an if statement without braces.

if ($var >= 0 )
echo "Square root is: ".sqrt($var);
else {
$negvar = -1*$var;
echo "Square root is: ".sqrt($var)."i";
}

If statements can be nested:

if ($var < 10) echo "var is less than 10"; elseif ($var < 20) echo "var is between 10 and 20"; elseif ($var < 30) echo "var is between 20 and 30"; else echo "var is greater than 30";

A compact (if cryptic) shorthand is useful:

echo "var is ".($var < 0 ? "negative" : "positive");

is equivalent to:

echo "var is ";
if ($var < 0) echo "negative"; else echo "positive";

The shorthand can be considered (expression ? true_value : false_value) where 'expression' is evaluated and, if true, the 'true_value' is returned, otherwise the 'false_value' is returned.

 

About Quinn McHenry

Quinn was one of the original co-founders of Tech-Recipes. He is currently crafting iOS applications as a senior developer at Small Planet Digital in Brooklyn, New York.
View more articles by Quinn McHenry

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