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PHP if...else...elseif Statements

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Conditional statements are used to perform different actions based on different conditions.

PHP Conditional Statements

Very often when you write code, you want to perform different actions for different conditions. You can use conditional statements in your code to do this.

In PHP we have the following conditional statements:

  • if statement - executes some code if one condition is true
  • if...else statement - executes some code if a condition is true and another code if that condition is false
  • if...elseif...else statement - executes different codes for more than two conditions
  • switch statement - selects one of many blocks of code to be executed

PHP - The if Statement

The if statement executes some code if one condition is true.

Syntax

if ( condition) {
  code to be executed if condition is true;
}

Example

Output "Have a good day!" if the current time (HOUR) is less than 20:

<?php
$t = date("H");

if ($t < "20") {
  echo "Have a good day!";
}
?>
Try it Yourself »

PHP - The if...else Statement

The if...else statement executes some code if a condition is true and another code if that condition is false.

Syntax

if ( condition) {
  code to be executed if condition is true;
} else {
   code to be executed if condition is false;
}

Example

Output "Have a good day!" if the current time is less than 20, and "Have a good night!" otherwise:

<?php
$t = date("H");

if ($t < "20") {
  echo "Have a good day!";
} else {
  echo "Have a good night!";
}
?>
Try it Yourself »

PHP - The if...elseif...else Statement

The if...elseif...else statement executes different codes for more than two conditions.

Syntax

if ( condition) {
  code to be executed if this condition is true;
} elseif ( condition) {
  code to be executed if first condition is false and this condition is true;
} else {
   code to be executed if all conditions are false;
}

Example

Output "Have a good morning!" if the current time is less than 10, and "Have a good day!" if the current time is less than 20. Otherwise it will output "Have a good night!":

<?php
$t = date("H");

if ($t < "10") {
  echo "Have a good morning!";
} elseif ($t < "20") {
  echo "Have a good day!";
} else {
  echo "Have a good night!";
}
?>
Try it Yourself »

Short Hand If

To write shorter code, you can write if statements on one line.

Example

One-line if statement:

<?php
$a = 5;

if ($a < 10) $b = "Hello";

echo $b
?>
Try it Yourself »

Short Hand If...Else

If...else statements can also be written in one line, but the syntax is a bit different.

Example

One-line if...else statement:

<?php
$a = 13;

$b = $a < 10 ? "Hello" : "Good Bye";

echo $b;
?>
Try it Yourself »

This technique is known as Ternary Operators, or Conditional Expressions.

Nested If

You can have if statements inside if statements, this is called nested if statements.

Example

An if inside an if:

<?php
$a = 13;

if ($a > 10) {
  echo "Above 10";
  if ($a > 20) {
    echo " and also above 20";
  } else {
    echo " but not above 20";
  }
}
?>
Try it Yourself »

PHP - The switch Statement

The switch statement will be explained in the next chapter.

PHP Exercises

Test Yourself With Exercises

Exercise:

Output "Hello World" if $a is greater than $b.

$a = 50;
$b = 10;
  >  {
  echo "Hello World";
}


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