PHP If...Else Statements
The if, elseif and else statements in PHP are used to perform different actions based on different conditions.
Conditional Statements
Very often when you write code, you want to perform different actions for different decisions.
You can use conditional statements in your code to do this.
-
if...else
statement
- use this statement if you want to execute a set of code when a condition is
true and another if the condition is not true
-
elseif
statement
- is used with the if...else statement to execute a set of code if one
of several condition are true
The If...Else Statement
If you want to execute some code if a condition is true and another code if a condition is false, use the if....else statement.
Syntax
if (condition)
code to be executed if condition is true;
else
code to be executed if condition is false;
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Example
The following example will output "Have a nice weekend!" if the current day is Friday, otherwise it will output "Have a nice day!":
<html>
<body>
<?php
$d=date("D");
if ($d=="Fri")
echo "Have a nice weekend!";
else
echo "Have a nice day!";
?>
</body>
</html>
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If more than one line should be executed if a condition is true/false, the lines should be enclosed within curly braces:
<html>
<body>
<?php
$d=date("D");
if ($d=="Fri")
{
echo "Hello!<br />";
echo "Have a nice weekend!";
echo "See you on Monday!";
}
?>
</body>
</html>
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The ElseIf Statement
If you want to execute some code if one of several conditions are true use the elseif statement
Syntax
if (condition)
code to be executed if condition is true;
elseif (condition)
code to be executed if condition is true;
else
code to be executed if condition is false;
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Example
The following example will output "Have a nice weekend!" if the current day is Friday, and "Have a nice Sunday!" if the current day is Sunday. Otherwise it will output "Have a nice day!":
<html>
<body>
<?php
$d=date("D");
if ($d=="Fri")
echo "Have a nice weekend!";
elseif ($d=="Sun")
echo "Have a nice Sunday!";
else
echo "Have a nice day!";
?>
</body>
</html>
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PHP Switch Statement
The Switch statement in PHP is used to perform one of several different actions based on one of several different conditions.
The Switch Statement
If you want to select one of many blocks of code to be executed, use the Switch statement.
The switch statement is used to avoid long blocks of if..elseif..else code.
Syntax
switch (expression)
{
case label1:
code to be executed if expression = label1;
break;
case label2:
code to be executed if expression = label2;
break;
default:
code to be executed
if expression is different
from both label1 and label2;
}
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Example
This is how it works:
-
A single
expression (most often a variable) is evaluated once
-
The value of the
expression is compared with the values for each case in the structure
-
If there is a
match, the code associated with that case is executed
-
After a code is
executed, break is used to stop the code from running into the next
case
-
The default
statement is used if none of the cases are true
<html>
<body>
<?php
switch ($x)
{
case 1:
echo "Number 1";
break;
case 2:
echo "Number 2";
break;
case 3:
echo "Number 3";
break;
default:
echo "No number between 1 and 3";
}
?>
</body>
</html>
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