Merge and aggregate datasets: Difference between revisions
→{{header|Java}}
Line 954:
<syntaxhighlight>
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.DoubleSummaryStatistics;
import java.util.List;
public final class MergeAndAggregateDatasets {
public static void main(String[] args) {
List<Patient> patients = Arrays.asList(
new Patient("1001", "Hopper"),
new Patient("4004", "Wirth"),
new Patient("3003", "Kemeny"),
new Patient("2002", "Gosling"),
new Patient("5005", "Kurtz") );
List<Visit> visits = Arrays.asList(
new Visit("2002", "2020-09-10", 6.8),
new Visit("1001", "2020-09-17", 5.5),
new Visit("4004", "2020-09-24", 8.4),
new Visit("2002", "2020-10-08", null),
new Visit("1001", "" , 6.6),
new Visit("3003", "2020-11-12", null),
new Visit("4004", "2020-11-05", 7.0),
new Visit("1001", "2020-11-19", 5.3) );
Collections.sort(patients, Comparator.comparing(Patient::patientID));
System.out.println("| PATIENT_ID | LASTNAME | LAST_VISIT | SCORE_SUM | SCORE_AVG |");
for ( Patient patient : patients ) {
List<Visit> patientVisits = visits.stream().filter( v -> v.visitID == patient.patientID() ).toList();
String lastVisit = patientVisits.stream().map( v -> v.visitDate )
.max(Comparator.naturalOrder()).orElseGet( () -> " None " );
DoubleSummaryStatistics statistics = patientVisits.stream().filter( v -> v.score != null )
.mapToDouble(Visit::score).summaryStatistics();
double scoreSum = statistics.getSum();
double scoreAverage = statistics.getAverage();
String patientDetails = String.format("%12s%11s%13s%12.2f%12.2f",
patient.patientID, patient.lastName, lastVisit, scoreSum, scoreAverage);
System.out.println(patientDetails);
}
}
record Patient(String patientID, String lastName) {};
record Visit(String visitID, String visitDate, Double score) {};
}
</syntaxhighlight>
{{ out }}
<pre>
| PATIENT_ID | LASTNAME | LAST_VISIT | SCORE_SUM | SCORE_AVG |
1001 Hopper 2020-11-19 17.40 5.80
2002 Gosling 2020-10-08 6.80 6.80
3003 Kemeny 2020-11-12 0.00 0.00
4004 Wirth 2020-11-05 15.40 7.70
5005 Kurtz None 0.00 0.00
</pre>
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