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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:
<? // 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 } ?>
<? // 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:
<? $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:
<? // 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:
<? $number = 4; // Set $number equal to 4 // Use the curly braces if your code is more than one line if ($number == 5) // here is your code if the condition is true echo "Your number is 5"; elseif ($number == 2) // here is your code if the condition is true echo "Your number is 2"; else // here is your code if the condition is false echo "Your number is not 5 or 2"; ?>
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