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elseif/else if

(PHP 4, PHP 5)

elseif, as its name suggests, is a combination of if and else. Like else, it extends an if statement to execute a different statement in case the original if expression evaluates to FALSE. However, unlike else, it will execute that alternative expression only if the elseif conditional expression evaluates to TRUE. For example, the following code would display a is bigger than b, a equal to b or a is smaller than b:

<?php
if ($a $b) {
    echo 
"a is bigger than b";
} elseif (
$a == $b) {
    echo 
"a is equal to b";
} else {
    echo 
"a is smaller than b";
}
?>

There may be several elseifs within the same if statement. The first elseif expression (if any) that evaluates to TRUE would be executed. In PHP, you can also write 'else if' (in two words) and the behavior would be identical to the one of 'elseif' (in a single word). The syntactic meaning is slightly different (if you're familiar with C, this is the same behavior) but the bottom line is that both would result in exactly the same behavior.

The elseif statement is only executed if the preceding if expression and any preceding elseif expressions evaluated to FALSE, and the current elseif expression evaluated to TRUE.

Nota: Note that elseif and else if will only be considered exactly the same when using curly brackets as in the above example. When using a colon to define your if/elseif conditions, you must not separate else if into two words, or PHP will fail with a parse error.

<?php

/* Incorrect Method: */
if($a $b):
    echo 
$a." is greater than ".$b;
else if(
$a == $b): // Will not compile.
    
echo "The above line causes a parse error.";
endif;


/* Correct Method: */
if($a $b):
    echo 
$a." is greater than ".$b;
elseif(
$a == $b): // Note the combination of the words.
    
echo $a." equals ".$b;
else:
    echo 
$a." is neither greater than or equal to ".$b;
endif;

?>

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User Contributed Notes 5 notes

up
22
qualitycoder
8 months ago
The reason 'else if' (with a space) works with traditional syntax and not colon syntax is because of a technicality.

<?php
 
if($var == 'Whatever') {

  } else if(
$var == 'Something Else') {

  }
?>

In this instance, the 'else if' is a shorthand/inline else statement (no curly braces) with the if statement as a body. It is the same things as:

<?php
 
if($var == 'Whatever') {

  } else {
      if(
$var == 'Something Else') {

      }
  }
?>

If you were to write this with colon syntax, it would be:

<?php
 
if($var == 'Whatever'):

  else:
      if(
$var == 'Something Else'):

      endif;
  endif;
?>
up
31
Vladimir Kornea
8 years ago
The parser doesn't handle mixing alternative if syntaxes as reasonably as possible.

The following is illegal (as it should be):

<?
if($a):
    echo $a;
else {
    echo $c;
}
?>

This is also illegal (as it should be):

<?
if($a) {
    echo $a;
}
else:
    echo $c;
endif;
?>

But since the two alternative if syntaxes are not interchangeable, it's reasonable to expect that the parser wouldn't try matching else statements using one style to if statement using the alternative style. In other words, one would expect that this would work:

<?
if($a):
    echo $a;
    if($b) {
      echo $b;
    }
else:
    echo $c;
endif;
?>

Instead of concluding that the else statement was intended to match the if($b) statement (and erroring out), the parser could match the else statement to the if($a) statement, which shares its syntax.

While it's understandable that the PHP developers don't consider this a bug, or don't consider it a bug worth their time, jsimlo was right to point out that mixing alternative if syntaxes might lead to unexpected results.
up
-21
peter dot mlich at volny dot cz
1 year ago
To  Rudi / 3 years ago

Try switch in switch($name) case 'word': break; . --- slow
Try if/else and  if/elseif in $name='word'. --- in my fast test, place 3
Try isset in isset($array[$name]). ---  place 1
Try in_array in in_array($name,$array). --- slow
Try array_key_exists in array_key_exists($name,$array).

Try return (end function) in if/elseif with  -- place 2
if('word'==$name) {
  $parsed[$name]=$text;
  return;
  } 
elseif('word'==$name) {
  $parsed[$name]=$text;
  return;


PHP 5.35, xml_parse function, i parsed 9.2MB xml file to sql, script in place 1 do it at 11.54s (do more than only condition)
up
-11
Abhijit
3 months ago
/*If and elseif is the most used control among php. I personally love it and use them every now on then.

If and elseif gives you the power to create the main algorithm. For simple example it's Weekend or not.*/

$currentday="Monday";

if($currentday=="Sunday"){echo "Sunday is Fun day.";}
elseif($currentday=="Saturday"){echo "Great! No work for Two days.";}
else{echo "Work hard so that you could see the Weekend.";}

/*Now in here if change the value of $currentday to Monday, Tuesday, Wednesday, Thursday, Friday then You will get the output "Work hard so that you could see the Weekend".

However if you change $currentday as Saturday you will get output "Great! No work for Two days."
And for Sunday in $currentday you get "Sunday is Fun day."*/
up
-52
Anonymous
8 years ago
There is no good way to interpret the dangling else.  One must pick a way and apply rules based on that. 

Since there is no endif before an else, there is no easy way for PHP to know what you mean.
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