Snippets Algorithms
Algorithms
Generate a range of numbers
by: wall
|
October 24, 2001
Version: 1
Type: Function
Category: Algorithms
License: GNU General Public License
Description: Syntax: array steps(double start, double end, int steps) Returns an array of numbers, beginning with $start and gradually incrementing it so that the final number is $end. You decide how many numbers you want in the list, and the function will modify the incrementation accordingly. It will return a minimum of 2 munbers ($start and $end), no matter how small $steps is.
<?php
# Return a list with $steps elements, incrementing gradually from $start to $end.
# Example: steps(0,256,9) will return:
# array(0,32,64,96,128,160,192,224,256)
function steps($start, $end, $steps)
{
settype($start, double);
settype($end, double);
settype($steps, integer);
# Avoid division by zero...
if ($steps < 2)
$steps = 2;
# Initialise.
$return = array();
for ($i=0; $i<=$steps-1; $i++)
{
# In step 2 of 10 this will be 0.2.
$end_percent = $i / ($steps-1);
# In step 2 of 10 this will be 0.8.
$start_percent = 1-$end_percent;
# $start_percent + $end_percent will always be equal to 1.
$return[] = $start*$start_percent + $end*$end_percent;
}
return $return;
}
?>
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