I have an assignment where I have to read data from a text file. The data looks like this in the file:
1946-01-01;07:00:00;-1.8;G
1946-01-01;13:00:00;-1.0;G
1946-01-01;18:00:00;-1.9;G
1946-01-02;07:00:00;-1.7;G
I want to format the data and put it in an appropriate data structure so that I then can search for average temperature for all dates between two dates. What is the simplest way to format this data when my code is:
package algo.weatherdata;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.time.LocalDate;
import java.util.List;
/**
* Provides methods to retrieve temperature data from a weather station file.
*/
public class WeatherDataHandler {
/**
* Load weather data from file.
*
* #param filePath path to file with weather data
* #throws IOException if there is a problem while reading the file
*/
public void loadData(String filePath) throws IOException {
//Read all weather data
List<String> fileData = Files.readAllLines(Paths.get(filePath));
/**
* TODO: Format data and put it in appropriate data structure.
*/
}
You can iterate over your lines and separate each line by a delimiter (in your case ;):
public void loadData(String filePath) throws IOException {
List<String> fileData = Files.readAllLines(Paths.get(filePath));
String[] lineValues = str.split(";");
// line values are stored in this array
}
Then you can do with the array as you like (store them, process them).
Let's assume the following class that will contain weather data:
public class WeatherData {
private LocalDateTime dateTime;
private double temperature;
private String tag; // I don't really know what is 'G' mean
public WeatherData(LocalDateTime dateTime, double temperature, String tag) {
this.dateTime = dateTime;
this.temperature = temperature;
this.tag = tag;
}
}
Next, we analyze the data file into the current structure and collect them all into a list:
private List<WeatherData> weatherData = new ArrayList<>();
public void loadData(String filePath) throws IOException {
List<String> fileData = Files.readAllLines(Paths.get(filePath));
for(String str : fileData) {
List<String> parsed = parseData(str);
LocalDateTime dateTime = LocalDateTime.of(dateOf(parsed.get(0)),
timeOf(parsed.get(1)));
double temperature = Double.parseDouble(parsed.get(2));
String tag = parsed.get(3);
WeatherData weather = new WeatherData(dateTime, temperature, tag);
weatherData.add(weather);
}
}
private List<String> parseData(String s) {
return Arrays.asList(s.split(";"));
}
private LocalDate dateOf(String date) {
return LocalDate.parse(date);
}
private LocalTime timeOf(String time) {
return LocalTime.parse(time);
}
And then you could work with a list to search between dates and calculate the average temperature
I have tried above Dinar Zaripov piece of code in my work space with addition of generating getters methods for dateTime, temperature and tag.
Continuation after for loop
private static float averageTemperature(List<WeaterData> weatherData)
{
float sum = 0; // Variable to store the sum
float count = 0; // Variable to keep the count
if (weatherList != null) {
for (WeaterData averageWeather : weatherData) {
float value = averageWeather.getTemperature();
System.out.println(value);
if (value <= 0) { // Check if the number is negative
sum += value; // Add the value to the current sum
count++; // Increment the count by 1
}
}
}
return (count > 0) ? (sum /count) : 0; // Calculate the average if there were any negative numbers
}
But I am getting average as ** average::1.5999999 **
However as per the math it should be 1.6. could someone tell me how ? or this is correct ?
when I give below data , I am getting correct average :)
1946-01-01;07:00:00;-1.8;A
** 1946-01-01;13:00:00;-1.1; B**
1946-01-01;18:00:00;-1.9;C
1946-01-02;07:00:00;-1.7;D
Related
I am writing a Java program by using the Binance JAVA API to retrieve the 1-minute interval candelsticks of a trading pair. Using this Java class, I want to calculate the EMA (Exponential Moving Average) of the past 10 days.
The Binance JAVA API websocket implementation gets the latest depth events, which also contains the current closing price that I use to update the EMA calculation by calling the EMA#update method.
However, I notice that the EMA showing on the Binance's graph, does not correspond to the ones I get from my code. Also, I notice that the values need some time to 'settle' before giving (somewhat) same values compared to those shown on Binance.
On TradingView I found a formula to calculate the EMA (that shows the same EMA value as on Binance), but that is different than the one used in the EMA class. However, even when using this formula, the values are very different than the one on Binance.
Could someone help me figure out what the issue is and how to obtain the same values?
UPDATE 1: code provided
import java.util.*;
import java.util.stream.Collectors;
import com.binance.api.client.BinanceApiClientFactory;
import com.binance.api.client.BinanceApiRestClient;
import com.binance.api.client.BinanceApiWebSocketClient;
import com.binance.api.client.domain.market.Candlestick;
import com.binance.api.client.domain.market.CandlestickInterval;
import core.util.text.DecimalFormat;
import core.util.text.StringUtil;
public class test_003
{
private Map<Long, Candlestick> candlesticksCache = new TreeMap<>();
private EMA EMA_10;
private EMA EMA_20;
public static void main(String[] pArgs)
{
new test_003();
}
private test_003()
{
Locale.setDefault(Locale.US);
candlesticksCacheExample("ADAUSDT", CandlestickInterval.ONE_MINUTE);
}
private void candlesticksCacheExample(String symbol, CandlestickInterval interval)
{
initializeCandlestickCache(symbol, interval);
startCandlestickEventStreaming(symbol, interval);
}
private void initializeCandlestickCache(String symbol, CandlestickInterval interval)
{
BinanceApiClientFactory factory = BinanceApiClientFactory.newInstance();
BinanceApiRestClient client = factory.newRestClient();
List<Candlestick> candlestickBars_10 = client.getCandlestickBars(symbol.toUpperCase(), interval, Integer.valueOf(11), null, null);
List<Candlestick> candlestickBars_20 = client.getCandlestickBars(symbol.toUpperCase(), interval, Integer.valueOf(21), null, null);
List<Double> closingPriceList_10 = candlestickBars_10.stream().map(c -> Double.valueOf(c.getClose())).collect(Collectors.toList());
List<Double> closingPriceList_20 = candlestickBars_20.stream().map(c -> Double.valueOf(c.getClose())).collect(Collectors.toList());
EMA_10 = new EMA(closingPriceList_10, Integer.valueOf(10));
EMA_20 = new EMA(closingPriceList_20, Integer.valueOf(20));
}
private void startCandlestickEventStreaming(String symbol, CandlestickInterval interval)
{
BinanceApiClientFactory factory = BinanceApiClientFactory.newInstance();
BinanceApiWebSocketClient client = factory.newWebSocketClient();
client.onCandlestickEvent(symbol.toLowerCase(), interval, response -> {
Long openTime = response.getOpenTime();
Candlestick updateCandlestick = candlesticksCache.get(openTime);
if (updateCandlestick == null)
{
// new candlestick
updateCandlestick = new Candlestick();
}
// update candlestick with the stream data
updateCandlestick.setOpenTime(response.getOpenTime());
updateCandlestick.setOpen(response.getOpen());
updateCandlestick.setLow(response.getLow());
updateCandlestick.setHigh(response.getHigh());
updateCandlestick.setClose(response.getClose());
updateCandlestick.setCloseTime(response.getCloseTime());
updateCandlestick.setVolume(response.getVolume());
updateCandlestick.setNumberOfTrades(response.getNumberOfTrades());
updateCandlestick.setQuoteAssetVolume(response.getQuoteAssetVolume());
updateCandlestick.setTakerBuyQuoteAssetVolume(response.getTakerBuyQuoteAssetVolume());
updateCandlestick.setTakerBuyBaseAssetVolume(response.getTakerBuyQuoteAssetVolume());
// Store the updated candlestick in the cache
candlesticksCache.put(openTime, updateCandlestick);
double closingPrice = Double.valueOf(updateCandlestick.getClose());
EMA_10.update(closingPrice);
EMA_20.update(closingPrice);
System.out.println(StringUtil.replacePlaceholders("Closing price: %1 | EMA(10): %2 - EMA(20): %3", response.getClose(),
DecimalFormat.format(EMA_10.get(), "#.#####"),
DecimalFormat.format(EMA_20.get(), "#.#####")));
});
}
public class EMA
{
private double currentEMA;
private final int period;
private final double multiplier;
private final List<Double> EMAhistory;
private final boolean historyNeeded;
private String fileName;
public EMA(List<Double> closingPrices, int period)
{
this(closingPrices, period, false);
}
public EMA(List<Double> closingPrices, int period, boolean historyNeeded)
{
currentEMA = 0;
this.period = period;
this.historyNeeded = historyNeeded;
this.multiplier = 2.0 / (double) (period + 1);
this.EMAhistory = new ArrayList<>();
init(closingPrices);
}
public double get()
{
return currentEMA;
}
public double getTemp(double newPrice)
{
return (newPrice - currentEMA) * multiplier + currentEMA;
}
public void init(List<Double> closingPrices)
{
if (period > closingPrices.size()) return;
//Initial SMA
for (int i = 0; i < period; i++)
{
currentEMA += closingPrices.get(i);
}
currentEMA = currentEMA / (double) period;
if (historyNeeded) EMAhistory.add(currentEMA);
//Dont use latest unclosed candle;
for (int i = period; i < closingPrices.size() - 1; i++)
{
update(closingPrices.get(i));
}
}
public void update(double newPrice)
{
// EMA = (Close - EMA(previousBar)) * multiplier + EMA(previousBar)
currentEMA = (newPrice - currentEMA) * multiplier + currentEMA;
if (historyNeeded) EMAhistory.add(currentEMA);
}
public int check(double newPrice)
{
return 0;
}
public String getExplanation()
{
return null;
}
public List<Double> getEMAhistory()
{
return EMAhistory;
}
public int getPeriod()
{
return period;
}
}
}
UPDATE 2
The problem is that onCandlestickEvent is not just called when a candle is completed, but actually multiple times per minute (every 2 seconds or so). The data that you are receiving in the response spans the time from when the candle is opened until the event time of the response, whether the candle is completed or not.
To see what I mean, you could replace the System.out() statement in your startCandlestickEventStreaming method with the following:
System.out.println(response.getOpenTime() + ";" +
response.getEventTime() + ";" +
response.getCloseTime());
You will see that the close time of the candle actually lies in the future.
In order to update your EMA correctly, you will have to wait until the candle has actually been completed. You could store the open time of the tentative candle in a member variable, check if it has changed since the last time onCandlestickEvent was called, and then update your EMA with the final close value of the candle:
client.onCandlestickEvent(symbol.toLowerCase(), interval, response -> {
Long openTime = response.getOpenTime();
Candlestick updateCandlestick = candlesticksCache.get(openTime);
if (updateCandlestick == null)
{
// new candlestick
updateCandlestick = new Candlestick();
}
// update candlestick with the stream data
...
// Store the updated candlestick in the cache
candlesticksCache.put(openTime, updateCandlestick);
if (openTime > m_LastOpenTime)
{
// need to get the close of the PREVIOUS candle
Candlestick previousCandle = candlesticksCache.get(m_LastOpenTime);
double closingPrice = Double.valueOf(previousCandle.getClose());
EMA_10.update(closingPrice);
EMA_20.update(closingPrice);
System.out.println(StringUtil.replacePlaceholders("Closing price: %1 | EMA(10): %2 - EMA(20): %3", response.getClose(),
DecimalFormat.format(EMA_10.get(), "#.#####"),
DecimalFormat.format(EMA_20.get(), "#.#####")));
m_LastOpenTime = openTime;
}
});
You'll probably get an exception on the first response, because there are no candles on the stack yet and we don't have a m_LastOpenTime. You could get the current server time before calling client.onCandlestickEvent():
private void startCandlestickEventStreaming(String symbol, CandlestickInterval interval)
{
BinanceApiClientFactory factory = BinanceApiClientFactory.newInstance();
BinanceApiWebSocketClient client = factory.newWebSocketClient();
BinanceApiRestClient restClient = factory.newRestClient();
m_LastOpenTime = restClient.getServerTime();
client.onCandlestickEvent(symbol.toLowerCase(), interval, response -> {
...
}
}
I noticed there's actually a much simpler way than my other answer. I'm leaving that one up, however, because it could still be relevant for dealing with a dodgy connection where you can't necessarily rely on always getting the final candlestick with your response.
The response.getBarFinal()) method allows for testing whether the response you have received is the final candlestick or if it is just an intermediate one. If you change your code as follows, your EMA will only get updated with the final close value of the candle as it should be:
if (response.getBarFinal())
{
double closingPrice = Double.valueOf(updateCandlestick.getClose());
EMA_10.update(closingPrice);
EMA_20.update(closingPrice);
System.out.println(StringUtil.replacePlaceholders("Closing price: %1 | EMA(10): %2 - EMA(20): %3", response.getClose(),
DecimalFormat.format(EMA_10.get(), "#.#####"),
DecimalFormat.format(EMA_20.get(), "#.#####")));
}
I am trying to read a text file and store with a hashmap. The file contains information like this:
1946-01-12;13:00:00;0.3;G
1946-01-12;18:00:00;-2.8;G
1946-01-13;07:00:00;-6.2;G
1946-01-13;13:00:00;-4.7;G
1946-01-13;18:00:00;-4.3;G
1946-01-14;07:00:00;-1.5;G
1946-01-14;13:00:00;-0.2;G
I want to store the dates as keys and then "13:00:00;0.3;G" as value, where 13:00 is time, 0.3 is temperature and G represent a quality code. I wonder if this is even possbile since many rows in the file has the same date? I already wrote a code for storing the data in a list, but now I want to store it in a map instead. My old code looks like this:
/**
* Provides methods to retrieve temperature data from a weather station file.
*/
public class WeatherDataHandler {
private List<Weather> weatherData = new ArrayList<>();
public void loadData(String filePath) throws IOException {
List<String> fileData = Files.readAllLines(Paths.get("filepath"));
for(String str : fileData) {
List<String> parsed = parseData(str);
LocalDate date = LocalDate.parse(parsed.get(0));
LocalTime time = LocalTime.parse(parsed.get(1));
double temperature = Double.parseDouble(parsed.get(2));
String quality = parsed.get(3);
//new Weather object
Weather weather = new Weather(date, time, temperature, quality);
weatherData.add(weather);
}
}
private List<String> parseData(String s) {
return Arrays.asList(s.split(";"));
}
I got stuck when implementing the hashmap. I started with some code below, but I do not know how to loop over a sequence of dates. What is the simplest way to store the data from the file in a map?
public class WeatherDataHandler {
public void loadData(String filePath) throws IOException {
Map<LocalDate, String> map =new HashMap<LocalDate, String>();
BufferedReader br = new BufferedReader(new FileReader("filepath"));
String line="";
int i=0;
while (line != null) {
line = br.readLine();
map.put(i,line);
i++;
}
String date="";
String time="";
String temperature="";
String quality="";
for(int j=0;j<map.size();j++){
if(!(map.get(j)== null)){
String[] getData=map.get(j).toString().split("\\,");
date = getData[0];
time = getData[1];
temperature = getData[2];
quality = getData[3];
}
}
}
Using the stream API you can create a map where the key is the date and the [map] value is a list.
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
public class WeatherDataHandler {
public static void main(String[] args) {
Path path = Paths.get("filepath");
try {
Map<String, List<String>> map = Files.lines(path)
.collect(Collectors.groupingBy(line -> line.split(";", 2)[0]));
map.entrySet()
.stream()
.forEach(entry -> System.out.printf("%s = %s%n", entry.getKey(), entry.getValue()));
}
catch (IOException x) {
x.printStackTrace();
}
}
}
Method lines() in class java.nio.file.Files creates a stream where each stream element is a single line of the file being read.
Method split() splits the line into a two element array (because of the second argument which is the number 2).
The first array element, i.e. the date, becomes the [map] key and the rest of the line becomes the [map] value.
Whenever a duplicate key is encountered, the value is appended to the existing value creating a list. Hence the type parameters for the map are String for the [map] key and List<String> for the [map] value.
Running the above code on your sample data yields:
1946-01-14 = [1946-01-14;07:00:00;-1.5;G, 1946-01-14;13:00:00;-0.2;G]
1946-01-12 = [1946-01-12;13:00:00;0.3;G , 1946-01-12;18:00:00;-2.8;G]
1946-01-13 = [1946-01-13;07:00:00;-6.2;G , 1946-01-13;13:00:00;-4.7;G, 1946-01-13;18:00:00;-4.3;G ]
I am pretty new into programming and I have an assignment to make, but I got stuck.
I have to implement a program which will read a CSV file (1 million+ lines) and count how many clients ordered "x" distinct products on a specific day.
The CSV looks like this:
Product Name | Product ID | Client ID | Date
Name 544 86 10/12/2017
Name 545 86 10/12/2017
Name 644 87 10/12/2017
Name 644 87 10/12/2017
Name 9857 801 10/12/2017
Name 3022 801 10/12/2017
Name 3021 801 10/12/2017
The result from my code is:
801: 2 - incorrect
86: 2 - correct
87: 2 - incorrect
Desired output is:
Client 1 (801): 3 distinct products
Client 2 (86): 2 distinct products
Client 3 (87): 1 distinct product
Additionally,
If I want to know how many clients ordered 2 distinct products I would like a result to look like this:
Total: 1 client ordered 2 distinct products
If I want to know the maximum number of distinct products ordered in a day, I would like the result to look like this:
The maximum number of distinct products ordered is: 3
I tried to use a Hash Map and Multimap by Google Guava (my best guess here), but I couldn't wrap my head around it.
My code looks like this:
package Test;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.HashMultimap;
public class Test {
public static void main(String[] args) {
//HashMultimap<String, String> myMultimap = HashMultimap.create();
Map<String, MutableInteger> map = new HashMap<String, MutableInteger>();
ArrayList<String> linesList = new ArrayList<>();
// Input of file which needs to be parsed
String csvFile = "file.csv";
BufferedReader csvReader;
// Data split by 'TAB' in CSV file
String csvSplitBy = "\t";
try {
// Read the CSV file into an ArrayList array for easy processing.
String line;
csvReader = new BufferedReader(new FileReader(csvFile));
while ((line = csvReader.readLine()) !=null) {
linesList.add(line);
}
csvReader.close();
} catch (IOException e) {
e.printStackTrace();
}
// Process each CSV file line which is now contained within
// the linesList list Array
for (int i = 0; i < linesList.size(); i++) {
String[] data = linesList.get(i).split(csvSplitBy);
String col2 = data[1];
String col3 = data[2];
String col4 = data[3];
// Determine if Column 4 has the desired date
// and count the values
if (col4.contains("10/12/2017")) {
String key = col3;
if (map.containsKey(key)) {
MutableInteger count = map.get(key);
count.set(count.get() + 1);
} else {
map.put(key, new MutableInteger(1));
}
}
}
for (final String k : map.keySet()) {
if (map.get(k).get() == 2) {
System.out.println(k + ": " + map.get(k).get());
}
}
}
}
Any advise or suggestion on how this can be implemented would be greatly appreciated.
Thank you in advance guys.
You could store a Setof productIds per clientId, and just take the size of that.
As a Set does not allow duplicate values, this will effectively give you the distinct number of productIds.
Also, I recommend that you give your variables meaningful name instead of col2, k, map... This will make your code more readable.
Map<String, Set<String>> distinctProductsPerClient = new HashMap<String, Set<String>>();
// Process each CSV file line which is now contained within
// the linesList list Array
// Start from 1 to skip the first line
for (int i = 1; i < linesList.size(); i++) {
String line = linesList.get(i);
String[] data = line.split(csvSplitBy);
String productId = data[1];
String clientId = data[2];
String date = data[3];
// Determine if Column 4 has the desired date
// and count the values
if (date.contains("10/12/2017")) {
if (!distinctProductsPerClient.containsKey(clientId)) {
distinctProductsPerClient.put(clientId, new HashSet<>());
}
distinctProductsPerClient.get(clientId).add(productId);
}
}
for (final String clientId : distinctProductsPerClient.keySet()) {
System.out.println(clientId + ": " + distinctProductsPerClient.get(clientId).size());
}
More advanced solution using Stream API (requires Java 9)
If you introduce the class OrderData(that represents a single line in the CSV) like this:
private static class OrderData {
private final String productName;
private final String productId;
private final String clientId;
private final String date;
public OrderData(String csvLine) {
String[] data = csvLine.split("\t");
this.productName = data[0];
this.productId = data[1];
this.clientId = data[2];
this.date = data[3];
}
public String getProductName() {
return productName;
}
public String getProductId() {
return productId;
}
public String getClientId() {
return clientId;
}
public String getDate() {
return date;
}
}
you can replace the for loop with this:
Map<String, Set<String>> distinctProductsPerClient2 = linesList.stream()
.skip(1)
.map(OrderData::new)
.collect(groupingBy(OrderData::getClientId, mapping(OrderData::getProductId, toSet())));
But I reckon this might be a little bit to complex if you're new into programming (although it might be a good exercise if you would try to understand what the above code does).
I am working on a project where I have been given a text file and I have to add up the points for each team and printout the top 5 teams.
The text file looks like this:
FRAMae Berenice MEITE 455.455<br>
CHNKexin ZHANG 454.584<br>
UKRNatalia POPOVA 453.443<br>
GERNathalie WEINZIERL 452.162<br>
RUSEvgeny PLYUSHCHENKO 191.399<br>
CANPatrick CHAN 189.718<br>
CHNHan YAN 185.527<br>
CHNCheng & Hao 271.018<br>
ITAStefania & Ondrej 270.317<br>
USAMarissa & Simon 264.256<br>
GERMaylin & Daniel 260.825<br>
FRAFlorent AMODIO 179.936<br>
GERPeter LIEBERS 179.615<br>
JPNYuzuru HANYU 197.9810<br>
USAJeremy ABBOTT 165.654<br>
UKRYakov GODOROZHA 160.513<br>
GBRMatthew PARR 157.402<br>
ITAPaul Bonifacio PARKINSON 153.941<br>
RUSTatiana & Maxim 283.7910<br>
CANMeagan & Eric 273.109<br>
FRAVanessa & Morgan 257.454<br>
JPNNarumi & Ryuichi 246.563<br>
JPNCathy & Chris 352.003<br>
UKRSiobhan & Dmitri 349.192<br>
CHNXintong &Xun 347.881<br>
RUSYulia LIPNITSKAYA 472.9010<br>
ITACarolina KOSTNER 470.849<br>
JPNMao ASADA 464.078<br>
UKRJulia & Yuri 246.342<br>
GBRStacey & David 244.701<br>
USAMeryl &Charlie 375.9810<br>
CANTessa & Scott 372.989<br>
RUSEkaterina & Dmitri 370.278<br>
FRANathalie & Fabian 369.157<br>
ITAAnna & Luca 364.926<br>
GERNelli & Alexander 358.045<br>
GBRPenny & Nicholas 352.934<br>
USAAshley WAGNER 463.107<br>
CANKaetlyn OSMOND 462.546<br>
GBRJenna MCCORKELL 450.091<br>
The first three letters represent the team.
the rest of the text is the the competitors name.
The last digit is the score the competitor recived.
Code so far:
import java.util.Arrays;
public class project2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
String[] array = new String[41];
String[] info = new String[41];
String[] stats = new String[41];
String[] team = new String[41];
//.txt file location
FileInput fileIn = new FileInput();
fileIn.openFile("C:\\Users\\O\\Desktop\\turn in\\team.txt");
// txt file to array
int i = 0;
String line = fileIn.readLine();
array[i] = line;
i++;
while (line != null) {
line = fileIn.readLine();
array[i] = line;
i++;
}
//Splitting up Info/team/score into seprate arrays
for (int j = 0; j < 40; j++) {
team[j] = array[j].substring(0, 3).trim();
info[j] = array[j].substring(3, 30).trim();
stats[j] = array[j].substring(36).trim();
}
// Random stuff i have been trying
System.out.println(team[1]);
System.out.println(info[1]);
System.out.println(stats[1]);
MyObject ob = new MyObject();
ob.setText(info[0]);
ob.setNumber(7, 23);
ob.setNumber(3, 456);
System.out.println("Text is " + ob.getText() + " and number 3 is " + ob.getNumber(7));
}
}
I'm pretty much stuck at this point because I am not sure how to add each teams score together.
This looks like homework... First of all you need to examine how you are parsing the strings in the file.
You're saying: the first 3 characters are the country, which looks correct, but then you set the info to the 4th through the 30th characters, which isn't correct. You need to dynamically figure out where that ends and the score begins. There is a space between the "info" and the "stats," knowing that you could use String's indexOf function. (http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#indexOf(int))
Have a look at Maps.
A map is a collection that allows you to get data associated with a key in a very short time.
You can create a Map where the key is a country name, with value being the total points.
example:
Map<String,Integer> totalScore = new HashMap<>();
if (totalScore.containsKey("COUNTRYNAME"))
totalScore.put("COUNTRYNAME", totalScore.get("COUNTRYNAME") + playerScore)
else
totalScore.put("COUNTRYNAME",0)
This will add to the country score if the score exists, otherwise it will create a new totalScore for a country initialized to 0.
Not tested, but should give you some ideas:
public static void main(String... args)
throws Exception {
class Structure implements Comparable<Structure> {
private String team;
private String name;
private Double score;
public Structure(String team, String name, Double score) {
this.team = team;
this.name = name;
this.score = score;
}
public String getTeam() {
return team;
}
public String getName() {
return name;
}
public Double getScore() {
return score;
}
#Override
public int compareTo(Structure o) {
return this.score.compareTo(o.score);
}
}
File file = new File("path to your file");
List<String> lines = Files.readAllLines(Paths.get(file.toURI()), StandardCharsets.UTF_8);
Pattern p = Pattern.compile("(\\d+(?:\\.\\d+))");
List<Structure> structures = new ArrayList<Structure>();
for (String line : lines) {
Matcher m = p.matcher(line);
while (m.find()) {
String number = m.group(1);
String text = line.substring(0, line.indexOf(number) - 1);
double d = Double.parseDouble(number);
String team = text.substring(0, 3);
String name = text.substring(3, text.length());
structures.add(new Structure(team, name, d));
}
}
Collections.sort(structures);
List<Structure> topFive = structures.subList(0, 5);
for (Structure structure : topFive) {
System.out.println("Team: " + structure.getTeam());
System.out.println("Name: " + structure.getName());
System.out.println("Score: " + structure.getScore());
}
}
Just remove <br> from your file.
Loading file into memory
Your string splitting logic looks fine.
Create a class like PlayerData. Create one instance of that class for each row and set all the three fields into that using setters.
Keep adding the PlayerData objects into an array list.
Accumulating
Loop through the arraylist and accumulate the team scores into a hashmap. Create a Map to accumulate the team scores by mapping teamCode to totalScore.
Always store row data in a custom object for each row. String[] for each column is not a good way of holding data in general.
Take a look in File Utils. After that you can extract the content from last space character using String Utils e removing the <br> using it as a key for a TreeMap. Than you can have your itens ordered.
List<String> lines = FileUtils.readLines(yourFile);
Map<String, String> ordered = new TreeMap<>();
for (String s : lines) {
String[] split = s.split(" ");
String name = split[0].trim();
String rate = splt[1].trim().substring(0, key.length - 4);
ordered.put(rate, name);
}
Collection<String> rates = ordered.values(); //names ordered by rate
Of course that you need to adjust the snippet.
I'm trying to sort delimited files with a Time stamp | level | sensor name | measurement value structure so that all data associated with the sensor having the smallest time stamp would first be listed in increasing timestamp, then all the data associated with the sensor having the second smallest time stamp would be listed in increasing timestamp, etc…
Here’s an example of delimited file to be sorted :
20140102073500|1|sensor5|0.188|
20140102073502|1|sensor2|0.193|
20140102073600|2|sensor5|0.577|
20140102073603|2|sensor2|0.585|
20140102073700|3|sensor5|1.207|
20140102073702|3|sensor2|1.183|
Here what I want :
20140102073500|1|sensor5|0.188|
20140102073600|2|sensor5|0.577|
20140102073700|3|sensor5|1.207|
20140102073502|1|sensor2|0.193|
20140102073603|2|sensor2|0.585|
20140102073702|3|sensor2|1.183|
(note that I cannot sort by "sensor name / time stamp" because the sensor with the smallest time stamp changes from one file to the other...)
Here the coding I’m trying to work from (which only sort in ascending time stamp) :
import java.io.*;
import java.util.*;
public class Sort8 {
public static void main(String[] args) throws Exception {
Map<String, String> map;
try (BufferedReader reader = new BufferedReader(new FileReader("C:\\Test\\test.txt"))) {
map = new TreeMap<>();
String line;
while((line=reader.readLine())!=null){
map.put(getField(line),line);
System.out.println(getField(line));
}
System.out.println(map.values());
}
try (FileWriter writer = new FileWriter("C:\\Test\\test_sorted.txt")) {
for(String val : map.values()){
// System.out.println(val);
writer.write(val) ;
writer.write("\r\n");
}
}
}
private static String getField(String line) {
return ((line.split("\\|")[1])+(line.split("\\|")[3]));
}
}
I'm new to Java so thank in advance for the help you can provide !
Put a comparator in the construction of your tree map.
map = new TreeMap<>(new Comparator<String>() {
#Override
public int compare(String s1, String s2) {
String[] a1 = s1.split("|");
String[] a2 = s2.split("|");
// First compare sensor
int sensor1 = Integer.parseInt(a1[2].replace("sensor", ""));
int sensor2 = Integer.parseInt(a2[2].replace("sensor", ""));
if(sensor1 != sensor2) {
return Integer.valueOf(sensor1).compareTo(sensor2);
}
// Second compare timestamp
long time1 = Long.parseLong(a1[0]);
long time2 = Long.parseLong(a2[0]);
return Long.valueOf(time1).compareTo(time2);
}
});