Remove utility information from a transaction database (SPMF documentation)
This example explains how to remove utility information from a transaction database using the SPMF open-source data mining library.
How to run this example?
- If you are using the graphical interface, (1) choose the "Remove_utility_information_from_a_transaction_database" algorithm, (2) choose the input file DB_utility.txt (3) click "Run algorithm".
- If you want to execute this example from the command
line, then execute this command:
java -jar spmf.jar run Remove_utility_information_from_a_transaction_database DB_Utility.txt output.txt in a folder containing spmf.jar and the input file DB_Utility.txt. - If you are using the source code version of SPMF, launch the file "MainTestTransactionUtilityRemover.java" in the package ca.pfv.SPMF.tests.
What is this tool?
This tool is a small program that is designed to convert a transaction database with utility information to a transaction database that does not contain utility information. For example, this tool can be used to convert a database such as Foodmart, available on the dataset page of the SPMF website so that the dataset can be used with frequent itemset mining algorithm such as Apriori, FPGrowth, etc., and association rule mining algorithms.
What is the input?
The input is a transaction database with utility information.For example, lLet's consider the following database consisting of 5 transactions (t1,t2...t5) and 7 items (1, 2, 3, 4, 5, 6, 7). This database is provided in the text file "DB_utility.txt" in the package ca.pfv.spmf.tests of the SPMF distribution.
| Items | Transaction utility | Item utilities for this transaction | |
| t1 | 3 5 1 2 4 6 | 30 | 1 3 5 10 6 5 |
| t2 | 3 5 2 4 | 20 | 3 3 8 6 |
| t3 | 3 1 4 | 8 | 1 5 2 |
| t4 | 3 5 1 7 | 27 | 6 6 10 5 |
| t5 | 3 5 2 7 | 11 | 2 3 4 2 |
Each line of the database is:
- a set of items (the first column of the table),
- the sum of the utilities (e.g. profit) of these items in this transaction (the second column of the table),
- the utility of each item for this transaction (e.g. profit generated by this item for this transaction)(the third column of the table).
Note that the value in the second column for each line is the sum of the values in the third column.
What are real-life examples of such a database? There are several applications in real life. One application is a customer transaction database. Imagine that each transaction represents the items purchased by a customer. The first customer named "t1" bought items 3, 5, 1, 2, 4 and 6. The amount of money spent for each item is respectively 1 $, 3 $, 5 $, 10 $, 6 $ and 5 $. The total amount of money spent in this transaction is 1 + 3 + 5 + 10 + 6 + 5 = 30 $.
What is the output?
The output is a transaction database where the utility information has been removed. For example, the output of the above example is:
| Items | |
| t1 | 3 5 1 2 4 6 |
| t2 | 3 5 2 4 |
| t3 | 3 1 4 |
| t4 | 3 5 1 7 |
| t5 | 3 5 2 7 |
The output is written to a file (output.txt in this example).
Input file format
The input file format is defined as follows. It is a text file. Each lines represents a transaction. Each line is composed of three sections, as follows.
- First, the items contained in the transaction are listed. An item is represented by a positive integer. Each item is separated from the next item by a single space. It is assumed that all items within a same transaction (line) are sorted according to a total order (e.g. ascending order) and that no item can appear twice within the same transaction.
- Second, the symbol ":" appears and is followed by the transaction utility (an integer).
- Third, the symbol ":" appears and is followed by the utility of each item in this transaction (an integer), separated by single spaces.
For example, for the previous example, the input file is defined as follows:
3 5 1 2 4 6:30:1 3 5 10 6 5
3 5 2 4:20:3 3 8 6
3 1 4:8:1 5 2
3 5 1 7:27:6 6 10 5
3 5 2 7:11:2 3 4 2
Consider the first line. It means that the transaction {3, 5, 1, 2, 4, 6} has a total utility of 30 and that items 3, 5, 1, 2, 4 and 6 respectively have a utility of 1, 3, 5, 10, 6 and 5 in this transaction. The following lines follow the same format.
Output file format
The output file format is a transaction database. An item is represented by a positive integer. A transaction is a line in the text file. In each line (transaction), items are separated by a single space.
3 5 1 2 4 6
3 5 2 4
3 1 4
3 5 1 7
3 5 2 7