PHP: For Loops

For loop in PHP


Example: Simple for loop

PHP has a very classic syntax for its for loop, simiiar to C. The for loop contains three parts that control how many times the code will loop.

  1. $x=1 creates and assigns 1 to the counter variable
  2. $x <=4 is the test condition. The loop will run while this condition is true
  3. $x++ is the incrementer. Each time through the loop, the $x variable will increment by 1.

	<?php
		for ($x=1; $x <= 4; $x++)
		{
			echo "<p>x = $x</p>";
		}
	?>
	

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Example: Simple for loop - decrementer (counting down)


	<?php
		for ($x=4; $x >= 1; $x--)
		{
			echo "<p>x = $x</p>";
		}
	?>
	

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Example: Loop with nested If statement


	<?php
	  $answer = 6;
	  for ($x = 1; $x <= 6; $x++)
	  {
		 if ($x == $answer)
			echo "<p>That is the right answer.</p>";
		 else
			echo "<p>That is the wrong answer.</p>";
	   }
	?>
	

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Output:

  That is the wrong answer.

  That is the wrong answer.

  That is the wrong answer.

  That is the wrong answer.

  That is the wrong answer.

  That is the right answer.


Example: Loop with Math


	<?php
	  $y = 1;
	  while ($x < 6)
	  {
		 $y = $y + 2;
		 echo "<p>x equals $x, y equals $y.</p>";
		  $x++;
	   }
	?>
	

  x equals 1, y equals 3.
x equals 2, y equals 5.
x equals 3, y equals 7.
x equals 4, y equals 9.
x equals 5, y equals 11.


Example: Loop to scan for even/odd numbers


	<?php
	for ($x=1; $x < 10; $x++)
	{
		$result = $x % 2;         // % calculated modulus/mod
		if ($result == 0)
			echo "<p>$x is an even number.</p>";
		else 
			echo "<p>$x is an odd number.</p>";
	}
	?>
	

  1 is an odd number.
  2 is an even number.
  3 is an odd number.
  4 is an even number.
  5 is an odd number.
  6 is an even number.
  7 is an odd number.
  8 is an even number.
  9 is an odd number.


Example: Loop with an HTML Table


	<?php
	echo "<table style=\"border: solid;\">";
	echo "<tr><th>Value of X</th><th>X Squared</th></tr>";
	for ($x=1; $x <= 5; $x++)
	{
	   echo "<tr>";
	   echo "<td>$x</td>";
	   echo "<td>" . $x*$x . "</td>";
	   echo "</tr>";
	}
	   echo "</table>";
	?>
	

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Output

screenshot of Loop with an HTML Table


Example: For Loop to Create 10 Times Table