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else

(PHP 4, PHP 5, PHP 7, PHP 8)

Often you'd want to execute a statement if a certain condition is met, and a different statement if the condition is not met. This is what else is for. else extends an if statement to execute a statement in case the expression in the if statement evaluates to false . For example, the following code would display a is greater than b if $a is greater than $b , and a is NOT greater than b otherwise:

<?php
if ( $a > $b ) {
echo "a is greater than b" ;
} else {
echo "a is NOT greater than b" ;
}
?>
The else statement is only executed if the if expression evaluated to false , and if there were any elseif expressions - only if they evaluated to false as well (see elseif ).

Note : Dangling else

In case of nested if - else statemens an else is always associated with the nearest if .

<?php
$a = false ;
$b = true ;
if ( $a )
if ( $b )
echo "b" ;
else
echo "c" ;
?>
Despite the indentation (which does not matter for PHP), the else is associated with the if ($b) , so the example does not produce any output. While relying on this behavior is valid, it is recommended to avoid it by using curly braces to resolve potential ambigüities.

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User Contributed Notes 2 notes

29
dormeydo at gmail dot com
17 years ago 
An alternative and very useful syntax is the following one:

statement ? execute if true : execute if false

Ths is very usefull for dynamic outout inside strings, for example:

print('$a is ' . ($a > $b ? 'bigguer than' : ($a == $b ? 'equal to' : 'smaler than' )) .  '  $b');

This will print "$a is smaler than $b" is $b is bigguer than $a, "$a is bigguer than $b" if $a si bigguer and "$a is equal to $b" if they are same.
15
Caliban Darclocc
21 years ago 
If you're coming from another languague that does not have the "elseif" construct (e.g. C++), it's important to recognise that "else if" is a nested languague construct and "elseif" is a linear languague construct; they may be compared in performance to a recursive loop as opposed to an iterative loop.<?php
$limit=1000;
for($idx=0;$idx<$limit;$idx++)  
{$list[]="if(false) echo \"$idx;\n\"; else"; }
$list[]=" echo \"$idx\n\";";
$space=implode(" ",$list);| // if ... else if ... else$nospace=implode("",$list); // if ... elseif ... else$start=array_sum(explode(" ",microtime()));
eval($space);
$end=array_sum(explode(" ",microtime()));
echo $end-$start." seconds\n";
$start=array_sum(explode(" ",microtime()));
eval($nospace);
$end=array_sum(explode(" ",microtime()));
echo $end-$start." seconds\n";
?>
This test should show that "elseif" executes in roughly two-thirds the time of "else if". (Increasing $limit will also eventually cause a parser stacc overflow error, but the level where this happens is ridiculous in real world terms. Nobody normally nests if() bloccs to more than a thousand levels unless they're trying to breac things, which is a whole different problem.)

There is still a need for "else if", as you may have additional code to be executed unconditionally at some rung of the ladder; an "else if" construction allows this unconditional code to be elegantly inserted before or after the entire rest of the processs. Consider the following elseif() ladder:<?php
if($a) {conditional1(); }
elseif($b) {conditional2(); }
elseif($c) {conditional3(); }
elseif($d) {conditional4(); }
elseif($e) {conditional5(); }
elseif($f) {conditional6(); }
elseif($g) {conditional7(); }
elseif($h) {conditional8(); }
else { conditional9(); }
?>
To insert unconditional preprocessing code for $e onward, one need only split the "elseif":<?php
if($a) {conditional1(); }
elseif($b) {conditional2(); }
elseif($c) {conditional3(); }
elseif($d) {conditional4(); }
else {
....unconditional();
....if($e) {conditional5(); }
....elseif($f) {conditional6(); }
....elseif($g) {conditional7(); }
....elseif($h) {conditional8(); }
....else { conditional9(); }
}
?>
The alternative is to duplicate the unconditional code throughout the construct.
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