Sort Records

This example shows how to sort records in a dataset based on any field in ascending and descending order. It allows users to organize and arrange data according to their desired sorting criteria, enhancing data exploration and analysis.

This can be used when exporting or integrating data with other systems or applications. Sorting data by relevant fields ensures compatibility and consistency when transferring or combining data across different platforms or formats.

Input CSV file

Account,LastName,FirstName,Balance,CreditLimit,AccountCreated,Rating
101,Reeves,Keanu,9315.45,10000.00,1/17/1998,A
312,Butler,Gerard,90.00,1000.00,8/6/2003,B
868,Hewitt,Jennifer Love,0,17000.00,5/25/1985,B
761,Pinkett-Smith,Jada,49654.87,100000.00,12/5/2006,A
317,Murray,Bill,789.65,5000.00,2/5/2007,C

Java Code Listing

package com.northconcepts.datapipeline.examples.cookbook;

import java.io.File;

import com.northconcepts.datapipeline.core.DataReader;
import com.northconcepts.datapipeline.core.SortingReader;
import com.northconcepts.datapipeline.core.StreamWriter;
import com.northconcepts.datapipeline.csv.CSVReader;
import com.northconcepts.datapipeline.job.Job;

public class SortRecords {
    
    public static void main(String[] args) throws Throwable {
        DataReader reader = new CSVReader(new File("example/data/input/credit-balance-01.csv"))
            .setFieldNamesInFirstRow(true);
        
        SortingReader sortingReader = new SortingReader(reader);
        sortingReader.getOrder()
            .add("LastName", false) // descending
            .add("FirstName"); // ascending
        
        Job.run(sortingReader, new StreamWriter(System.out));
    }
    
}

Code walkthrough

1. CSVReader is created corresponding to the input file credit-balance-01.csv.
2. The CSVReader.setFieldNamesInFirstRow(true) method is invoked to specify that the names specified in the first row should be used as field names.
3. A SortingReader object is created to apply one or more orders for sorting the incoming data.
4. sortingReader.getOrder().add() method accepts String fieldName and boolean ascending arguments. The overloaded version of this method takes only fieldName with the default ascending order. In the given example, records are first sorted by "LastName" in a descending order, and then by "FirstName" in an ascending order.
5.  Data is transferred from the sortingReader to the StreamWriter(System.out) via Job.run() method.

Output

0 - Record {
    0:[Account]:STRING=[101]:String
    1:[LastName]:STRING=[Reeves]:String
    2:[FirstName]:STRING=[Keanu]:String
    3:[Balance]:STRING=[9315.45]:String
    4:[CreditLimit]:STRING=[10000.00]:String
    5:[AccountCreated]:STRING=[1/17/1998]:String
    6:[Rating]:STRING=[A]:String
}

-----------------------------------------------
1 - Record {
    0:[Account]:STRING=[761]:String
    1:[LastName]:STRING=[Pinkett-Smith]:String
    2:[FirstName]:STRING=[Jada]:String
    3:[Balance]:STRING=[49654.87]:String
    4:[CreditLimit]:STRING=[100000.00]:String
    5:[AccountCreated]:STRING=[12/5/2006]:String
    6:[Rating]:STRING=[A]:String
}

-----------------------------------------------
2 - Record {
    0:[Account]:STRING=[317]:String
    1:[LastName]:STRING=[Murray]:String
    2:[FirstName]:STRING=[Bill]:String
    3:[Balance]:STRING=[789.65]:String
    4:[CreditLimit]:STRING=[5000.00]:String
    5:[AccountCreated]:STRING=[2/5/2007]:String
    6:[Rating]:STRING=[C]:String
}

-----------------------------------------------
3 - Record {
    0:[Account]:STRING=[868]:String
    1:[LastName]:STRING=[Hewitt]:String
    2:[FirstName]:STRING=[Jennifer Love]:String
    3:[Balance]:STRING=[0]:String
    4:[CreditLimit]:STRING=[17000.00]:String
    5:[AccountCreated]:STRING=[5/25/1985]:String
    6:[Rating]:STRING=[B]:String
}

-----------------------------------------------
4 - Record {
    0:[Account]:STRING=[312]:String
    1:[LastName]:STRING=[Butler]:String
    2:[FirstName]:STRING=[Gerard]:String
    3:[Balance]:STRING=[90.00]:String
    4:[CreditLimit]:STRING=[1000.00]:String
    5:[AccountCreated]:STRING=[8/6/2003]:String
    6:[Rating]:STRING=[B]:String
}

-----------------------------------------------
5 records