In PHP you sometimes need your script to run different code if a condition it true or false. This is where the if/else statements come in to play. There is also a elseif statement that you may use when multiple conditions are true, we will look at examples of all this in a bit. If/Else statements can be troubling later if you don't comment them well, especially when you can a lot of them together, you go back later and can't remember what does what. So please be sure to comment your if/else statements well, as you should all of you code.
Basic If/Else Statement:
PHP Code
Example:
<?
// Use the curly braces if your code is
more than one line
if (condition) {
// here is your code if the condition is
true
// line two of your code
} else {
// here is your code if the condition is
false
// line two of your code
}
?>
PHP Code
Example:
<?
// You don't have to use the curly
braces if your code is one line
if (condition)
// here is your code if the condition is
true
else
// here is your code if the condition is
false
?>
Now lets look at a real example of the if/else in action by evaluating a condition.
Example If/Else Statement:
PHP Code
Example:
<?
$a =
5; // Set $a equal to
5
$b
= 2; // Set $b equal to 2
if
($a > $b) { // If $a is greater than $b
// here is your code if the condition is
true
echo
"a($a) is greater than
b($b)!";
} else {
// here
is your code if the condition is false
echo "a($a) is not greater than b($b) so the
expression is false";
}
?>
Now lets look at the elseif statement where we will evaluate multiple expressions.
Basic elseif Statement:
PHP Code Example:
<?
// Use the curly
braces if your code is more than one line
if (condition)
// here is your code if the condition is
true
elseif
(condition)
// here is your code if the condition is
true
else
// here is your code if the condition is
false
?>
Example elseif Statement:
PHP Code
Example:
<?$number
= 4; // Set $number equal to
4// Use the curly braces if your code is
more than one lineif ($number == 5)// here is your code if the condition is
trueecho "Your number is 5";elseif ($number == 2)// here is your code if the condition is
trueecho "Your number is 2";else// here is your code if the condition is
falseecho "Your number is not 5 or
2";?>
