PHP
5 while Loops
PHP
Loops
Often when
you write code, you want the same block of code to run over and over again in a
row. Instead of adding several almost equal code-lines in a script, we can use
loops to perform a task like this.
In PHP, we
have the following looping statements:
while -
loops through a block of code as long as the specified condition is true
do...while -
loops through a block of code once, and then repeats the loop as long as the
specified condition is true
for - loops
through a block of code a specified number of times
foreach -
loops through a block of code for each element in an array
The PHP
while Loop
The while
loop executes a block of code as long as the specified condition is true.
Syntax
while
(condition is true) {
code to be executed;
}
The example
below first sets a variable $x to 1 ($x = 1). Then, the while loop will
continue to run as long as $x is less than, or equal to 5 ($x <= 5). $x will
increase by 1 each time the loop runs ($x++):
Example
<?php
$x
= 1;
while($x
<= 5) {
echo "The number is: $x
<br>";
$x++;
}
?>
The PHP
do...while Loop
The
do...while loop will always execute the block of code once, it will then check
the condition, and repeat the loop while the specified condition is true.
Syntax
do
{
code to be executed;
}
while (condition is true);
The example
below first sets a variable $x to 1 ($x = 1). Then, the do while loop will
write some output, and then increment the variable $x with 1. Then the
condition is checked (is $x less than, or equal to 5?), and the loop will
continue to run as long as $x is less than, or equal to 5:
Example
<?php
$x
= 1;
do
{
echo "The number is: $x
<br>";
$x++;
}
while ($x <= 5);
?>
Notice that
in a do while loop the condition is tested AFTER executing the statements
within the loop. This means that the do while loop would execute its statements
at least once, even if the condition is false the first time.
The example
below sets the $x variable to 6, then it runs the loop, and then the condition
is checked:
Example
<?php
$x
= 6;
do
{
echo "The number is: $x
<br>";
$x++;
}
while ($x <= 5);
?>
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