Conditional statements 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.
In PHP we have the following conditional statements:
- if statement - use this
statement to execute some code only if a specified condition is true
- if...else
statement - use this
statement to execute some code if a condition is true and another code if
the condition is false
- if...elseif....else
statement - use this
statement to select one of several blocks of code to be executed
- switch
statement - use this
statement to select one of many blocks of code to be executed
The if Statement
Use
the if statement to execute some code only if a specified condition is true.
Syntax
if (condition) code to be executed if condition is
true;
The
following example will output "Have a nice weekend!" if the current
day is Friday:
<html>
<body>
<?php
$d=date("D");
if ($d=="Fri") echo "Have a nice weekend!";
?>
</body>
</html>
Notice
that there is no ..else.. in this syntax. The code is executed only if the specified condition is
true.<body>
<?php
$d=date("D");
if ($d=="Fri") echo "Have a nice weekend!";
?>
</body>
</html>
The if...else Statement
Use
the if....else statement to execute some code if a condition is true and
another code if a condition is false.
Syntax
if (condition)
{
code to be executed if condition is true;
}
else
{
code to be executed if condition is false;
}
{
code to be executed if condition is true;
}
else
{
code to be executed if condition is false;
}
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>
<body>
<?php
$d=date("D");
if ($d=="Fri")
{
echo "Have a nice weekend!";
}
else
{
echo "Have a nice day!";
}
?>
</body>
</html>
The if...elseif....else Statement
Use
the if....elseif...else statement to select one of several blocks of code to be
executed.
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;
}
{
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;
}
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>
<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>
