Category: Web Development

My brother needed to figure out how to do a “moving average” in some code he was writing a while ago. I’d never done this before and couldn’t find any really simple code examples so ended up on Wikipedia where I found it’s actually called a cumulative moving average.

Super simple code example follows:

<?php
$numbers = array(1,2,3,4);

// A simple function to calculate averages
function average($array)
{
	return (array_sum($array) / count($array));
}

/*
 * Simple function to calculate moving average with the following parameters
 * $datapoint - the most recently acquired new datapoint
 * $average - the current average
 * $count - the total number of items we're dealing with
 */
function cumulativeAverage($datapoint, $average, $count)
{
	return $average + (($datapoint - $average) /  $count);
}


// First let's print the average calculated normally so we can compare to the final result
print "Normal average:\t\t".average($numbers)."\n";


// $lastav stores the most recently calculated average
$lastav = 0;

// Loop through all the numbers in the array and calculate the cumulative average each time
for ($i = 0; $i<sizeof($numbers);$i++)
{
	$lastav = cumulativeAverage($numbers[$i], $lastav, $i+1);
}

print "Cumulative Average:\t".$lastav."\n";

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We regularly get people asking us about issues (real and imaginary) on our websites. There are a variety of frustrating ways users can report problems with websites, including the favourite classic – “it doesn’t work”.

If you’re ever on a website and it has a problem or something isn’t working as expected, you should definitely take the time to report it. Problems often can go completely unnoticed by the development team, especially on large websites, and it’s only when they’re actually brought to someone’s attention that they are fixed.

However, if you are going to report a problem with a website, then there’s a couple of things you should try to remember to include, at an absolute bare minimum, to help the people at the other end know what you’re talking about:

1) A URL. This is the bit of text in the address bar that shows what page you are on. It looks like http://www.sitename.com/pagename/, and without it the site developers will probably have no idea what you’re talking about.

2) Some information about what you were doing at the time. Even simple things like saying what you clicked on or what you were reading can provide useful information.

3) Information about your computer, including what web browser you’re using (if you don’t know, it’s probably Internet Explorer) and what operating system you’re running.

Anything else you can add would be gravy, but including this data will greatly help anyone that is reading your request try to figure out how to help you!