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PHP For Loops

Welcome! In this section we going to cover the use of for loops in PHP.

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• 1. For Loops
• 1.1 For Loop Syntax
• 2. PHP For Loop

For Loops

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A for loop is used when we want to execute a block of code for certain number of times. For example, printing a value 5 times.

For Loop Syntax

for(initialize counter; condition until counter is reached; increment counter)
{
	//execute block of code
}

For loop has three statements.

• In the first statement, we initialize a counter variable to an number value.
• In the second statement, we set a condition (a max/min number value) until the counter is reached.
• In the third statement, we set a value by how much we want the counter variable to incremented by.

Lets look at an example to see how to create a for loop in PHP.

PHP For Loop

Example - Print number through 0 to 5 with PHP For Loop

<?php

	for($i=0; $i<=5; $i=$i+1)
	{
		echo $i." ";
	}

?>

In the above example, we set a counter variable $i to 0. In the second statement of our for loop, we set the condition value to our counter variable $i to 5, i.e. the loop will execute until $i reaches 5. In the third statement, we set $i to increment by 1.

The above code will output numbers through 0 to 5 as 0 1 2 3 4 5.

Example - Print number through 5 to 0 with PHP For Loop

What if we want to go backwards, that is, print number though 0 to 5 in reverse order? We simple initialize the counter variable $i to 5, set its condition to 0 and decrement $i by 1.

<?php

	for($i=5; $i>=0; $i=$i-1)
	{
		echo $i." ";
	}

?>

The above code will output number from 5 to 0 as 5 4 3 2 1 0 looping backwards.

Example - Print table with alternate colors using PHP For Loop

Let's have a look an interesting example of php for loop. You often seen tables cell with alternate colors on different websites. So, let say we want to print the numbers in a table with alternate colors. This is how we would do it.

<?php
	echo "<table width='100' align='center'>";
	for($i=0; $i<=5; $i=$i+1)
	{
		if($i % 2 == 0)
		{
			echo "<tr>";
			echo "<td style='background-color:red'>";
			echo $i;
			echo "</td>";
			echo "</tr>";
		}
		else
		{
			echo "<tr>";
			echo "<td style='background-color:green'>";
			echo $i;
			echo "</td>";
			echo "</tr>";
		}
	}
	echo "</table>";
?>

The above code sets different background color to the table cells depending on the value of $i. If $i is divisible by 2, which means if it is even then display color green, otherwise display color red.

Now that we are fimiliar with PHP for loop. Now, let's take a look at the last type of loop, the while loop in PHP.

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