Loops in PHP are used to execute the same block of code a specified number of times. PHP supports following four loop types.
For Loop:
loops through a block of code a specified number of times.
Syntax:
for (initialization; condition; increment)
{
code to be executed;
}
Example:
The following example makes five iterations and changes the assigned value of two variables on each pass of the loop:
<html>
<body>
<?php
$a = 0;
$b = 0;
for( $i=0; $i<5; $i++ )
{
$a += 10;
$b += 5;
}
echo ("At the end of the loop a=$a and b=$b" );
?>
</body>
</html>
Result:
At the end of the loop a=50 and b=25
While Loop:
loops through a block of code if and as long as a specified condition is true.
Syntax:
while (condition)
{
code to be executed;
}
Example:
This example decrements a variable value on each iteration of the loop and the counter increments until it reaches 10 when the evaluation is false and the loop ends.
<html>
<body>
<?php
$i = 0;
$num = 50;
while( $i < 10)
{
$num--;
$i++;
}
echo ("Loop stopped at i = $i and num = $num" );
?>
</body>
</html>
Result:
Loop stopped at i = 10 and num = 40
Do While Loop:
loops through a block of code once, and then repeats the loop as long as a special condition is true.
Syntax:
do
{
code to be executed;
}while (condition);
Example:
The following example will increment the value of i at least once, and it will continue incrementing the variable i as long as it has a value of less than 10:
<html>
<body>
<?php
$i = 0;
$num = 0;
do
{
$i++;
}while( $i < 10 );
echo ("Loop stopped at i = $i" );
?>
</body>
</html>
Result:
Loop stopped at i = 10
Foreach Loop:
loops through a block of code for each element in an array.
We will discuss about continue and break keywords used to control the loops execution.
Syntax:
foreach (array as value)
{
code to be executed;
}
Example:
Try out following example to list out the values of an array.
<html>
<body>
<?php
$array = array( 1, 2, 3, 4, 5);
foreach( $array as $value )
{
echo "Value is $value <br />";
}
?>
</body>
</html>
Result:
Value is 1
Value is 2
Value is 3
Value is 4
Value is 5
No comments:
Post a Comment