w3resource

PHP break Statement

Description

Sometimes a situation arises where we want to exit from a loop immediately without waiting to get back to the conditional statement.

The keyword break ends execution of the current for, foreach, while, do while or switch structure. When the keyword break executed inside a loop the control automatically passes to the first statement outside the loop. A break is usually associated with the if.

Example:

In the following example we test the value of $sum, if it is greater than 1500 the break statement terminate the execution of the code. As the echo statement is the first statement outside loop it will print the current value of $sum.

<?php
$array1=array(100, 1100, 200, 400, 900);
$x1=0;
$sum=0
while ($x1<=4)
{
if ($sum>1500)
{
break;
}
$sum = $sum+$array1[$x1];
$x1=$x1+1;
}
echo $sum;
?>

Output:

1800 

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PHP: Tips of the Day

PHP represents "no value" with the null keyword. It's somewhat similar to the null pointer in C-language and to the NULL value in SQL.

Setting the variable to null:

Example:

$nullvar = null; // directly
function doSomething() {} // this function does not return anything
$nullvar = doSomething(); // so the null is assigned to $nullvar

Checking if the variable was set to null:

if (is_null($nullvar)) { /* variable is null */ }
if ($nullvar === null) { /* variable is null */ }

Null vs undefined variable

If the variable was not defined or was unset then any tests against the null will be successful but they will also generate a Notice: Undefined variable: nullvar:

$nullvar = null;
unset($nullvar);
if ($nullvar === null) { /* true but also a Notice is printed */ }
if (is_null($nullvar)) { /* true but also a Notice is printed */ }

Therefore undefined values must be checked with isset:

if (!isset($nullvar)) { /* variable is null or is not even defined */ }