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https://github.com/pharo-ai/a-priori
Implementation of A-Priori algorithm in Pharo
https://github.com/pharo-ai/a-priori
apriori-algorithm data-mining data-science frequent-itemsets pharo
Last synced: 3 months ago
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Implementation of A-Priori algorithm in Pharo
- Host: GitHub
- URL: https://github.com/pharo-ai/a-priori
- Owner: pharo-ai
- License: mit
- Created: 2019-10-30T01:15:55.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2023-12-19T14:35:20.000Z (11 months ago)
- Last Synced: 2024-05-20T23:03:36.033Z (6 months ago)
- Topics: apriori-algorithm, data-mining, data-science, frequent-itemsets, pharo
- Language: Smalltalk
- Size: 138 KB
- Stars: 2
- Watchers: 3
- Forks: 1
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-pharo - pharo-ai / APriori - Fast algorithm for mining frequent sets of items and finding association rules between items in a database of transactions. (Artificial Intelligence and Machine Learning)
README
# APriori
[](https://github.com/pharo-ai/APriori/actions/workflows/test.yml)
[](https://coveralls.io/github/pharo-ai/APriori?branch=master)
[](https://pharo.org/download)
[](https://pharo.org/download)
[](https://pharo.org/download)
[](https://pharo.org/download)
[](https://raw.githubusercontent.com/pharo-ai/APriori/master/LICENSE)
Implementation of A-Priori algorithm in Pharo
## Installation
To install APriori, go to the Playground (`Ctrl+OW`) in your [Pharo](https://pharo.org/) image and execute the following Metacello script (select it and press Do-it button or `Ctrl+D`):
```smalltalk
Metacello new
repository: 'github://pharo-ai/a-priori:v1.0.0';
baseline: 'AIAPriori';
load.
```
## How to use it?
Create a list of transactions. Each transaction is an itemset (for example, a list of products that were purchased together by one customer).
```Smalltalk
transactions := #(
(eggs milk butter)
(milk cereal)
(eggs bacon)
(bread butter)
(bread bacon eggs)
(bread avocado butter bananas)).
transactionsSource := APrioriTransactionsArray from: transactions.
```
Initialize an APriori algorithm with transactions:
```Smalltalk
apriori := APriori forTransactions: transactionsSource.
```
Specify the support threshold:
```Smalltalk
apriori minSupport: 1/3.
```
Alternatively, you could specify a minimum count threshold:
```Smalltalk
apriori minCount: 2.
```
Now you can find frequent itemsets - sets of items that are likely to be purchased together:
```Smalltalk
apriori findFrequentItemsets.
```
The result will be stored in the frequentItemsets instance variable of apriori:
```Smalltalk
apriori frequentItemsets.
anArray(
{bread, butter}
{eggs, bacon}
)
```
You can generate association rules from those frequent itemsets in the form `key => value` where a set of items `value` will be recommended to a customer who purchases a set of items `key`:
```Smalltalk
apriori buildAssociationRules.
```
The result will be stored in the associationRules instance variable of apriori:
```Smalltalk
apriori associationRules.
" anArray(
{bread} => {butter}
{butter} => {bread}
{eggs} => {bacon}
{bacon} => {eggs}
)"
```
Every itemset knows its count and support:
```Smalltalk
itemset := itemsets first. "{bread, butter}"
itemset count. "2"
itemset support. "1/3"
```
Similarly, every rule knows its count, support, confidence, and lift:
```Smalltalk
rule := rules first. "{bread} => {butter}"
rule count. "2"
rule support. "1/3"
rule confidence. "2/3"
rule lift. "4/3"
```
## Real-world example
Download the [Groceries dataset](https://github.com/stedy/Machine-Learning-with-R-datasets/blob/master/groceries.csv). It contains 1 month (30 days) of real-world point-of-sale transaction data from a typical local grocery outlet. The dataset contains 9835 transactions and the items are aggregated to 169 categories. We load the contents of `groceries.csv` into Pharo, split it by lines and then by commas to get a collection of transactions:
```Smalltalk
file := '/path/to/groceries.csv' asFileReference.
lines := Character lf split: file contents.
groceries := lines collect: [ :line | $, split: line ].
```
Now we initialize an A-Priori algorithm with support threshold of 1% and confidence threshold of 50%:
```Smalltalk
apriori := APriori
transactions: groceries
supportThreshold: 0.01
confidenceThreshold: 0.5.
```
We generate association rules (this can take about a minute):
```Smalltalk
rules := apriori associationRules.
```
And sort them by lift in descending order:
```Smalltalk
rules sort: [ :a :b | a lift > b lift ].
```
This will produce the following 15 rules:
```
{citrus fruit, root vegetables} => {other vegetables}
{root vegetables, tropical fruit} => {other vegetables}
{rolls/buns, root vegetables} => {other vegetables}
{root vegetables, yogurt} => {other vegetables}
{curd, yogurt} => {whole milk}
{butter, other vegetables} => {whole milk}
{root vegetables, tropical fruit} => {whole milk}
{root vegetables, yogurt} => {whole milk}
{domestic eggs, other vegetables} => {whole milk}
{whipped/sour cream, yogurt} => {whole milk}
{rolls/buns, root vegetables} => {whole milk}
{other vegetables, pip fruit} => {whole milk}
{tropical fruit, yogurt} => {whole milk}
{other vegetables, yogurt} => {whole milk}
{other vegetables, whipped/sour cream} => {whole milk}
```
Which means that we will recommend `other vegetables` to the customers who purchased `citrus fruit` and `root vegetables`. And for those who took `curd` and `yogurt` we will recommend the `whole milk`.