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Java 根據 csv 文件中的列數據提取計數

Java

慕尼黑5688855 2022-06-08 16:40:59

我有下面的 Java 代碼和 TestData.csv（輸入文件），我的預期輸出如下所示。但它顯示了我嘗試了很多的實際計數。任何人對此都有任何想法。任何幫助都是有價值的。根據列數據，我想要特定值的計數。package com;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.util.Arrays;import com.opencsv.CSVWriter;import com.opencsv.CSVReader;import java.time.format.DateTimeFormatter;import java.time.LocalDateTime;public class TestDataProcess { public static void main(String args[]) throws IOException { processData(); } public static void processData() { String[] trafficDetails; int locColumnPosition, subCcolumnPosition, j, i, msgTypePosition, k, m, trafficLevelPosition; String masterCSVFile, dayFolderPath; String[] countryID = { "LOC1" }; String[] subID = { "S1" }; String[] mType = { "MSG1" }; String[] trafficLevel = { "1", "2", "3" }; String columnNameLocation = "CountryID"; String columnNameSubsystem = "SubID"; String columnNameMsgType = "Type"; String columnNameAlrmLevel = "TrafficLevel"; masterCSVFile = "D:\\TestData.csv"; dayFolderPath = "D:\\output\\"; DateTimeFormatter dtf = DateTimeFormatter.ofPattern("dd_MM_yyyy"); LocalDateTime now = LocalDateTime.now(); System.out.println(dtf.format(now)); int count = 0; for (i = 0; i < countryID.length; i++) { count = 0; for (j = 0; j < subID.length; j++) { count = 0; String locaIdSubsysId = dtf.format(now) + "_" + countryID[i] + "_" + subID[j] + ".csv"; try (CSVWriter csvWriter = new CSVWriter(new FileWriter(dayFolderPath + locaIdSubsysId, true));

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紫衣仙女

TA貢獻1839條經驗獲得超15個贊

您可以使用 aMap將流量級別存儲為鍵，并將 csv 文件中的所有行List作為其值。然后只需打印List.

請參閱以下示例并查看代碼注釋：

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.TreeMap;

public class ExampleMain {

public static void main(String[] args) {

// create a Path object from the path to your file

Path csvFilePath = Paths.get("Y:\\our\\path\\to\\file.csv");

// create a data structure that stores data rows per traffic level

Map<Integer, List<DataRow>> dataRowsPerTrafficLevel = new TreeMap<Integer, List<DataRow>>();

try {

// read all the lines of the file

List<String> lines = Files.readAllLines(csvFilePath);

// iterate all the lines, skipping the header line

for (int i = 1; i < lines.size(); i++) {

// split the lines by the separator (WHICH MAY DIFFER FROM THE ONE USED HERE)

String[] lineValues = lines.get(i).split(",");

// store the value from column 6 (index 5) as the traffic level

int trafficLevel = Integer.valueOf(lineValues[5]);

// if the map already contains this key, just add the next data row

if (dataRowsPerTrafficLevel.containsKey(trafficLevel)) {

DataRow dataRow = new DataRow();

dataRow.subId = lineValues[1];

dataRow.countryId = lineValues[2];

dataRow.type = lineValues[3];

dataRowsPerTrafficLevel.get(trafficLevel).add(dataRow);

} else {

/* otherwise create a list, then a data row, add it to the list and put it in

* the map along with the new key

List<DataRow> dataRows = new ArrayList<DataRow>();

DataRow dataRow = new DataRow();

dataRow.subId = lineValues[1];

dataRow.countryId = lineValues[2];

dataRow.type = lineValues[3];

dataRows.add(dataRow);

dataRowsPerTrafficLevel.put(trafficLevel, dataRows);

}

// print the result

dataRowsPerTrafficLevel.forEach((trafficLevel, dataRows) -> {

System.out.println("For TrafficLevel " + trafficLevel + " there are " + dataRows.size()

+ " data rows in the csv file");

});

} catch (IOException e) {

e.printStackTrace();

}

* small holder class that just holds the values of columns 3, 4 and 5.

* If you want to have distinct values, make this one a full POJO implementing Comparable

static class DataRow {

String subId;

String countryId;

String type;

}

反對回復 2022-06-08

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Java 根據 csv 文件中的列數據提取計數

Java 根據 csv 文件中的列數據提取計數

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