array

I was saddened to hear of the passing of the Mathematician John Horton Conway today so I decided to put together a post on his 'game of life' simulator.

This game of life, more commonly called Conway's game of life, was devised by John Conway in 1970 and is a way of modelling very simple cell population dynamics. The game takes place on a two dimensional board containing a grid of orthogonal cells. The game is technically a zero player game in that the initial setup of the game dictates the eventual evolution of the board.

The sieve of Eratosthenes is named after Eratosthenes of Cyrene who was a Greek mathematician who devised a mechanism to find a sequence of prime numbers using a simple algorithm.

Normally, looping through a list of numbers and finding the primes can be an expensive process. The seive of Eratosthenes is one of the most efficient way of working out all of the smaller prime numbers below (below 10 million or so).

It is usual when writing a list of items to separate each item with a comma, except the last two items, which are separated with the word "and". I recently needed to implement a function that took a string and converted it into a list of this type so I thought I would expand on it and post it here.

Use the following array to print out a list of Canadian states, also know as provinces.

Use the following array if you want to print out a list of USA states either as a list, or as a select box.

Use the following code to create an array of counties in the UK.

If you have an object or array that you want to save until a later you can use the serialize() and unserialize() functions. The operation of the functions are straightforward. To serialize() an array just pass the serialise function the array like this.

The array_flip() function in PHP is used to swap the values of an array with the keys. Take the following array.

Working out the average of a bunch of values is quite a common task, but rather than looping through the array, adding together values as you go and the using the count() function to find out the average at the end.

Appending arrays in PHP can be done with the array_merge() function. The array will take any number of arrays as arguments and will return a single array. Here is an example using just two arrays.