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Conditional statements in PHP with examples
PHP conditional statements: In this article, we are going to learn about the various conditional statements in PHP programming language with examples.
Submitted by Kongnyu Carine, on April 02, 2024
While coding, you may get to a point where your results can only be gotten when a condition is valid. We make use of conditional statements. Conditional statements are statements that can only be executed based on the fulfillment of a particular condition(s).
There are basically 4 different types of conditional statements in PHP,
- The if statement
- The if...else statement
- The if...elseif...else statements
- The nested if...else statements
- The switch statement
With the if statement your code only executes only when the condition is true.
Syntax
if(condition){
//code to be executed when condition is true
}
Example
Let's check if a mark entered is greater than or equal to 80. If true an A grade is given.
<?php
//defining a variable
$mark = 120;
if ($mark >= 80) {
echo "you have an A";
}
?>
Output
you have an A
The if...else statement is used when a condition is satisfied and when it is not satisfied. So it's used when the condition is either true or false.
Syntax
if (condition){
//code to be executed when true }
else {
//code to be executed when false
}
Example
Here, we are going to check if the letter entered is an F which will display female else we display male.
<?php
//defining a variable
$gender = "F";
if ($gender == "F") {
echo "FEMALE";
} else {
echo "MALE";
}
?>
Output
FEMALE
In a situation where you have several conditions, for example a program to grade students based on their marks with the letters A, B, C, D, F. the if...elseif...else is used for this.
Syntax
if (condition1){
//code 1 to be executed
}
elseif(condition2) {
//code 2 to be executed
}
else{
//code to be executed if code 1 and code 2 are not true
}
Example
We are going to grade students with the letters A, B, C, D, F based on their marks on 100.
<?php
//defining a variable
$marks = 75;
if ($marks > 79) {
echo "A";
} elseif ($marks <= 79 && $marks > 60) {
echo "B";
} elseif ($marks <= 60 && $marks > 50) {
echo "C";
} elseif ($marks = 50) {
echo "D";
} else {
echo "F";
}
?>
Output
B
When you find if...else statements inside an if...else statement the statements are nested. With this statement, you can get alternatives results when a condition is true or false.
if (condition 1 )
{
if (condition 2 )
{
// code1 to be executed
}
else
{
// code 2 to be executed
}
}
else
{
// code 4 to be executed
}
Example
Let's compare two numbers using the nested if statement.
<?php
// defining variables
$number1 = 40;
$number2 = 12;
if ($number1 != $number2) {
echo "number1 is different from number2";
echo "<br>";
if ($number1 > $number2) {
echo "number1 is greater than number2";
} else {
echo "number2 is greater than number1";
}
} else {
echo "number1 is equal to number2";
}
?>
Output
number1 is different from number2
number2 is greater than number1
The switch statement is very similar to the if...else statement. But in the cases where your conditions are complicated like you need to check a condition with multiple constant values, a switch statement is preferred to an if...else. The examples below will help us better understand the switch statements.
switch (n)
{
case constant1:
// code to be executed if n is equal to constant1;
break;
case constant2:
// code to be executed if n is equal to constant2;
break;
.
.
.
default:
// code to be executed if n doesn't match any constant
}
Example
Let's rewrite the example of if...else statements using switch statements,
<?php
//variable definition
$gender = "M";
switch ($gender) {
case "F":
echo "F is FEMALE";
break;
case "M":
echo "M is MALE";
break;
default:
echo "Invalid choice";
}
?>
Output
M is MALE
To understand the above examples, you should have the knowledge of the following PHP Topics: