Use a for loop:
<?php
for ($i = $start; $i <= $end; $i++) {
plot_point($i);
}
?>
You can increment using values other than 1. For example:
<?php
for ($i = $start; $i <= $end; $i += $increment) {
plot_point($i);
}
?>
If you want to preserve the numbers for use beyond iteration,
use the range( ) method:
<?php
$range = range($start, $end);
?>
Loops like this are common. For instance, you could be plotting
a function and need to calculate the results for multiple points
on the graph. Or you could be a student counting down the number
of seconds until the end of school.
The for loop method uses a single integer and you have great
control over the loop, because you can increment and decrement
$i freely. Also, you can modify $i from inside the loop.
In the last example in the Solution, range( ) returns an array
with values from $start to $end. The advantage of using range( )
is its brevity, but this technique has a few disadvantages. For
one, a large array can take up unnecessary memory. Also, you're
forced to increment the series one number at a time, so you can't
loop through a series of even integers, for example.
It's valid for $start to be larger than $end. In this case,
the numbers returned by range( ) are in descending order. Also,
you can use it to retrieve character sequences:
<?php
print_r(range('l', 'p'));
?>
Array
(
[0] => l
[1] => m
[2] => n
[3] => o
[4] => p
)