Apriori Algorithm

Implementation of the Apriori algorithm in PHP. Main Page

Usage

First step:

include 'class.apriori.php'; 
$Apriori = new Apriori();

Methods

setMaxScan(int), setMinSup(int), setMinConf(int), setDelimiter(string), getMinSup(void), getMinConf(void), getMaxScan(void), getDelimiter(void), process(string or array), printFreqItemsets(void), getFreqItemsets(void), printAssociationRules(void), getAssociationRules(void), saveFreqItemsets(string), saveAssociationRules(string)

Initialize

Initialize options:

$Apriori->setMaxScan(20);       //Scan 2, 3, ...
$Apriori->setMinSup(2);         //Minimum support 1, 2, 3, ...
$Apriori->setMinConf(75);       //Minimum confidence - Percent 1, 2, ..., 100
$Apriori->setDelimiter(',');    //Delimiter

dataset.txt

A, B, C, D 
A, D, C
B, C
A, E, C

Example

minSup = 2, minConf = 75(%)

Coding

<?php   
include 'class.apriori.php';
 
$Apriori = new Apriori();
 
$Apriori->setMaxScan(20);       //Scan 2, 3, ...
$Apriori->setMinSup(2);         //Minimum support 1, 2, 3, ...
$Apriori->setMinConf(75);       //Minimum confidence - Percent 1, 2, ..., 100
$Apriori->setDelimiter(',');    //Delimiter 
 
/*
Use Array:
$dataset   = array();
$dataset[] = array('A', 'B', 'C', 'D'); 
$dataset[] = array('A', 'D', 'C');  
$dataset[] = array('B', 'C'); 
$dataset[] = array('A', 'E', 'C'); 
$Apriori->process($dataset);
*/
$Apriori->process('dataset.txt');
 
//Frequent Itemsets
echo '<h1>Frequent Itemsets</h1>';
$Apriori->printFreqItemsets();
 
echo '<h3>Frequent Itemsets Array</h3>';
print_r($Apriori->getFreqItemsets()); 
 
//Association Rules
echo '<h1>Association Rules</h1>';
$Apriori->printAssociationRules();
 
echo '<h3>Association Rules Array</h3>';
print_r($Apriori->getAssociationRules()); 
 
//Save to file
$Apriori->saveFreqItemsets('freqItemsets.txt');
$Apriori->saveAssociationRules('associationRules.txt');
?>

Result

Frequent Itemsets

Time: 0 second(s)
===============================================================================
{B,C} = 2
{A,C,D} = 2

Frequent Itemsets Array

Array
(
    [0] => Array
        (
            [sup] => 2
            [0] => B
            [1] => C
        )

    [1] => Array
        (
            [sup] => 2
            [0] => A
            [1] => C
            [2] => D
        )

)

Association Rules

Time: 0 second(s)
===============================================================================
B => C = 100%
D => C = 100%
D => A = 100%
D => A,C = 100%
C => A = 75%
A => C = 100%
A,D => C = 100%
C,D => A = 100%

Association Rules Array

Array
(
    [B] => Array
        (
            [C] => 100
        )

    [D] => Array
        (
            [C] => 100
            [A] => 100
            [A,C] => 100
        )

    [C] => Array
        (
            [A] => 75
        )

    [A] => Array
        (
            [C] => 100
        )

    [A,D] => Array
        (
            [C] => 100
        )

    [C,D] => Array
        (
            [A] => 100
        )

)