PHP Loops

Loops are blocks of code that execute a specified number of times. Using loops reduces the number of lines of code.

PHP works with 4 different types of loops:

• While loop
• Do...while loop
• For loop
• Foreach loop

While loop

The while loop continues to excecute as long as the specified condition is true.

<?php
   while(condition is true) 
   {
      execute code;
   }
?>

Example:

<?php  
  $x = 1;
   while($x <= 3) 
   { 
     echo "x=$x ";
     $x++;
   } 
?>

Output: 
 x=1 x=2 x=3
  

Do...while loop

In the do...while loop the block of code is executed before the condition is checked.

<?php
   do {
     execute code;
   } while (condition);
?>

Example:

<?php
$x= 1;
   do {
     echo "x=$x ";
     $x++;
   } while ($x < 5);
?>

Output: 
 x=1 x=2 x=3 x=4

For loop

The for loop is used when the number of times the block is to be executed is known in advance.

<?php
   for (variable initialisation; test condition; increment)
   { 
     execute code; 
   }
?>

Example:

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

Output:
 x=1 x=2 x=3 x=4

Foreach loop

The foreach loop helps in traversing through arrays.

<?php
  foreach ($array as $value)
  { 
    executable code; 
  }
?>

Example:

<?php
$numbers= array("One", "Two", "Three"); 
 foreach ($numbers as $value)
 {
   echo "$value ";
 }
?>

Output:
 One Two Three