Develop Reference

List<Cluster<DoublePoint>> to Set<DoublePoint>

I am trying to use DBSCANClusterer(apache.math3) to sort a Set of points which I generate and write it to a file. At this point, I am stuck here:
public Set<DoublePoint> DBSCAN(Set<DoublePoint> set2) {
Set<DoublePoint> points = new Set<DoublePoint>();
DBSCANClusterer<DoublePoint> dbscan = new DBSCANClusterer<DoublePoint>(1, 15);
//run dbscan on set of points
List<Cluster<DoublePoint>> clusters = dbscan.cluster(set2);
**sorted = clusters???**
How can I assign: List<Cluster<DoublePoint>> clusters to Set<DoublePoint> sorted?? I guess it should be something like 2D->1D!
And here is the rest of my code:
import java.awt.Point;
import java.io.*;
import java.util.*;
import org.apache.commons.math3.ml.clustering.Cluster;
import org.apache.commons.math3.ml.clustering.DBSCANClusterer;
import org.apache.commons.math3.ml.clustering.DoublePoint;
import java.util.HashSet;
import java.util.Random;
import java.util.Set;
public class Main {
public static void main(final String[] args) throws Exception {
new Main().run();
}
public void run() {
Set<DoublePoint> set = generateSetPoints();
try {
writeToFile(set, "points");
} catch(IOException ex) {
System.out.println("IO Exception while writing to file");
}
Set<DoublePoint> set_by_dbscan = dbScan(set);//
try {
writeToFile(set_by_dbscan, "by_dbscan");
} catch(IOException ex) {
System.out.println("IO Exception while writing to file");
}
}
public Set<DoublePoint> generateSetPoints() {
int xx=100;
int yy=100;
Set<DoublePoint> set = new HashSet<>();
Random rnd = new Random();
int number=100;
do{
int tmp[] = new int[2];
tmp[0] = rnd.nextInt(xx);
tmp[1] = rnd.nextInt(yy);
DoublePoint rndpoint = new DoublePoint(tmp);
set.add(rndpoint);
}
while (set.size()<number);
return set;
}
public void writeToFile(Set<DoublePoint> set, String filename) throws IOException {
File fout = new File( filename + ".txt");
FileOutputStream fos = new FileOutputStream(fout);
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos));
for (DoublePoint p: set) {
bw.write(p.getPoint()[0] + "," + p.getPoint()[1]);
bw.newLine();
}
bw.close();
}
public Set<DoublePoint> dbScan(Set<DoublePoint> set2) {
Set<DoublePoint> points = new Set<DoublePoint>();
DBSCANClusterer dbscan = new DBSCANClusterer(1, 15);
List<Cluster<DoublePoint>> clusters = dbscan.cluster(set2);
return clusters;
}
}

A HashSet is an unsorted data structure.
If you want sorted to be sorted, use something that retains order.
sorted = nes HashSet<>() is a real WTF...
Also, DBSCAN is not meant for sorting. Use OPTICS clustering instead.

How to Access variable from another class in same package in java

I want to access the class Totalnoofwords in class newrepeatedcount.
I want to print "a" of class Totalnoofwords megring with
System.out.println("( "+file1.getName() +" )-" +"Total words counted:"+total);
in class newrepeatedcount.
So I could run both the code for getting System.out.println("( "+file1.getName() +" )-" +" Total no of words=" + a +"Total repeated words counted:"+total);
Here is the snippet of 1 output which I wanted
( filenameBlog 39.txt )-Total no of words=83,total repeated words counted:4
Any suggestions Welcomed.
I am a beginner to java.
Here is my two class codes below.:)
Totalnoofwords.java
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
import org.apache.commons.io.FileUtils;
public class Totalnoofwords
{
public static void main(String[] args)
{
FilenameFilter filter = new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.endsWith(".txt");
}
};
File folder = new File("E:\\testfolder");
File[] listOfFiles = folder.listFiles(filter);
for (int i = 0; i < listOfFiles.length; i++) {
File file1 = listOfFiles[i];
try {
String content = FileUtils.readFileToString(file1);
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader ins = null;
try {
ins = new BufferedReader (
new InputStreamReader(
new FileInputStream(file1)));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
String line = "", str = "";
int a = 0;
int b = 0;
try {
while ((line = ins.readLine()) != null) {
str += line + " ";
b++;
}
} catch (IOException e) {
e.printStackTrace();
}
StringTokenizer st = new StringTokenizer(str);
while (st.hasMoreTokens()) {
String s = st.nextToken();
a++;
}
System.out.println(" Total no of words=" + a );
}
}
}
newrepeatedcount.java
package ramki;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStreamReader;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
public class newrepeatedcount {
public static void main(String[] args){
FilenameFilter filter = new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.endsWith(".txt");
}
};
File folder = new File("E:\\testfolder\\");
File[] listOfFiles = folder.listFiles(filter);
for (int i = 0; i < listOfFiles.length; i++) {
File file1 = listOfFiles[i];
try {
String content = FileUtils.readFileToString(file1);
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader ins = null;
try {
ins = new BufferedReader ( new InputStreamReader(new FileInputStream(file1)));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String st = null;
try {
st = IOUtils.toString(ins);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//split text to array of words
String[] words=st.split("\\s");
//frequency array
int[] fr=new int[words.length];
//init frequency array
for(int i1=0;i1<fr.length;i1++)
fr[i1]=-1;
//count words frequency
for(int i1=0;i1<words.length;i1++){
for(int j=0;j<words.length;j++){
if(words[i1].equals(words[j]))
{
fr[i1]++;
}
}
}
//clean duplicates
for(int i1=0;i1<words.length;i1++){
for(int j=0;j<words.length;j++){
if(words[i1].equals(words[j]))
{
if(i1!=j) words[i1]="";
}
}
}
//show the output
int total=0;
//System.out.println("Duplicate words:");
for(int i1=0;i1<words.length;i1++){
if(words[i1]!=""){
//System.out.println(words[i1]+"="+fr[i1]);
total+=fr[i1];
}
}
//System.out.println("Total words counted: "+total);
//System.out.println("Total no of repeated words : "+total+" ");
System.out.println("( "+file1.getName() +" )-" +"Total repeated words counted:"+total);
}
}}
I tried to put both the code into a single class
but neither one of the variable is working
System.out.println("( "+file1.getName() +" )-" +" Total no of words=" + a +"Total repeated words counted:"+total);
When I run neither "a" or "total" is working.(vice versa) If i change the code (variable)order.
Anyone tell how should I get both the variable output??
:)
Here is my updated code.below.
package ramki;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
public class newrepeatedcount {
public static void main(String[] args){
FilenameFilter filter = new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.endsWith(".txt");
}
};
File folder = new File("E:\\testfolder\\");
File[] listOfFiles = folder.listFiles(filter);
for (int i = 0; i < listOfFiles.length; i++) {
File file1 = listOfFiles[i];
try {
String content = FileUtils.readFileToString(file1);
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader ins = null;
try {
ins = new BufferedReader ( new InputStreamReader(new FileInputStream(file1)));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String line = "", str = "";
String st = null;
try {
st = IOUtils.toString(ins);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//split text to array of words
String[] words=st.split("\\s");
//frequency array
int[] fr=new int[words.length];
//init frequency array
for(int i1=0;i1<fr.length;i1++)
fr[i1]=-1;
//count words frequency
for(int i1=0;i1<words.length;i1++){
for(int j=0;j<words.length;j++){
if(words[i1].equals(words[j]))
{
fr[i1]++;
}
}
}
//clean duplicates
for(int i1=0;i1<words.length;i1++){
for(int j=0;j<words.length;j++){
if(words[i1].equals(words[j]))
{
if(i1!=j) words[i1]="";
}
}
}
int a = 0;
try {
while ((line = ins.readLine()) != null) {
str += line + " ";
}
} catch (IOException e) {
e.printStackTrace();
}
StringTokenizer st1 = new StringTokenizer(str);
while (st1.hasMoreTokens()) {
String s = st1.nextToken();
a++;
}
int total=0;
for(int i1=0;i1<words.length;i1++){
if(words[i1]!=""){
//System.out.println(words[i1]+"="+fr[i1]);
total+=fr[i1];
}
}
System.out.println("( "+file1.getName() +" )-" +"Total repeated words counted:"+total+","+"total no of words:"+a);
// System.out.println("total no of words:"+a);
}
}}

package Packagename;
public class newrepeatedcount {
public static void main(String[] args){
Totalnoofwords B=new Totalnoofwords();
B.somename();
System.out.println("a:"+B.a);
}
}

The variables inside the main function cannot be accessed from other class.
So you can modify Totalnoofwords.java something like.
package Packagename;
public class Totalnoofwords
{
static int a = 1;
public void somename(){
Totalnoofwords A=new Totalnoofwords();
A.a+=5;
System.out.println("a"+A.a);
}
}
and your newrepeatedcount.java be like
package Packagename;
public class newrepeatedcount {
public static void main(String[] args){
Totalnoofwords B=new Totalnoofwords();
B.somename();
System.out.println("a:"+B.a);
}
}

It looks like you have 2 main methods in the same package, I'm not sure if you wanted it this way or not, but this won't work because your not overloading the methods. For instance currently you have public static void main(String[] args) in one class, If you change the other class to accept an extra argument public static void main(String[] args1, String[]args2).
Also in order to access your second class, as stated above you would use something like
Totalnoofwords totalNoofWords = new Totalnoofwords();
totalNoofWords.accessSomething();
But this won't work, because you don't have a constructor.

reading in a file from computer and editing it and saving as a new file

I am trying to load in a file from my computer with all the words of the dictionary in the file.
When I load the file i put the words into an array of strings.
I then want to eliminate all words that have more than 9 letters in them.
I then want to save the words that are 9 letters or smaller into another separate text file.
When i try to open the new file it only has 9 words in it, yet my print to the screen on eclipse will print the all words of nine or less letters.
Can anyone help!
This is a program that was gave to me as part of the question.
import java.io.*;
public class FileIO{
public String[] load(String file) {
File aFile = new File(file);
StringBuffer contents = new StringBuffer();
BufferedReader input = null;
try {
input = new BufferedReader( new FileReader(aFile) );
String line = null;
int i = 0;
while (( line = input.readLine()) != null){
contents.append(line);
i++;
contents.append(System.getProperty("line.separator"));
}
}
catch (FileNotFoundException ex) {
System.out.println("Can't find the file - are you sure the file is in this location: "+file);
ex.printStackTrace();
}
catch (IOException ex){
System.out.println("Input output exception while processing file");
ex.printStackTrace();
}
finally {
try {
if (input!= null) {
input.close();
}
}
catch (IOException ex) {
System.out.println("Input output exception while processing file");
ex.printStackTrace();
}
}
String[] array = contents.toString().split("\n");
for(String s: array){
s.trim();
}
return array;
}
public void save(String file, String[] array) throws FileNotFoundException, IOException {
File aFile = new File(file);
Writer output = null;
try {
output = new BufferedWriter( new FileWriter(aFile) );
for(int i=0;i<array.length;i++){
output.write( array[i] );
output.write(System.getProperty("line.separator"));
}
}
finally {
if (output != null) output.close();
}
}
}
this is the class i tried to use
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.*;
public class countdown{
public static void main(String args[]){
FileIO reader = new FileIO();
Scanner scan = new Scanner(System.in);
String[] inputs = reader.load("C:/Users/Sony/Documents/dict.csv"); //Reading the File as a String array from a file called dict
String[] input = new String[inputs.length]; //new String array for strings less than 9 letters
for(int i=0;i<inputs.length;i++){
if(inputs[i].length()<=9) { //if string of index i is less than 9
input[i]=inputs[i]; //add it to the new array called input
System.out.println(input[i]); //print line to check
}
}
try{
reader.save("C:/Users/Sony/Documents/dictnew.csv",input);
//this is where i save it to the new file called dictnew.
}catch (Exception e){
System.out.println(e.getClass());
}
}
}

After reading how you want you can split rest logic remains same.
package com.srijan.playground;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class FilterLengthWords {
public static void main(String[] args) throws IOException {
BufferedReader br = null;
BufferedWriter bw = null;
try {
br = new BufferedReader(new FileReader("Sample.txt"));
bw = new BufferedWriter(new FileWriter("Output.txt"));
String tmp = null;
while((tmp=br.readLine())!=null) {
if(tmp.length()<=9) {
bw.write(tmp);
}
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(br!=null) {
br.close();
br=null;
}
if(bw!=null){
bw.close();
bw=null;
}
}
}
}
Thanks

Take numbers from a file and sort them

I need to make my program read a file, then take the numbers in the string and sort them into an array. I can get my program to read the file and put it to a string, but that's where I'm stuck. All the numbers are on different lines in the file, but appear as one long number in the string. This is what I have so far:
public static void main(String[] args) {
String ipt1;
Scanner fileInput;
File inFile = new File("input1.dat");
try {
fileInput = new Scanner(inFile);
//Reads file contents
while (fileInput.hasNext()) {
ipt1 = fileInput.next();
System.out.print(ipt1);
}
fileInput.close();
}
catch (FileNotFoundException e) {
System.out.println(e);
}
}

I recommend reading the values in as numeric types using fileInput.nextInt() or whatever type you want them, putting them in an array and using a built in sort like Arrays.sort. Unless I'm missing a more subtle point about the question.

If your task is just to get input from some file and you're sure the file has integers, use an ArrayList.
import java.util.*;
Scanner fileInput;
ArrayList<Double>ipt1 = new ArrayList<Double>();
File inFile = new File("input1.dat");
try {
fileInput = new Scanner(inFile);
//Reads file contents
while (fileInput.hasNext()){
ipt1.add(fileInput.nextDouble()); //Adds the next Double to the ArrayList
System.out.print(ipt1.get(ipt1.size()-1)); //Prints out what you just got.
}
fileInput.close();
}
catch (FileNotFoundException e){
System.out.println(e);
}
//Sorting time
//This uses the built-in Array sorting.
Collections.sort(ipt1);
However, if you DO need to come up with a simple array in the end, but CAN use ArrayLists, you can add the following:
Double actualResult[] = new Double[ipt1.size()]; //Declare array
for(int i = 0; i < ipt1.size(); ++i){
actualResult[i] = ipt1.get(i);
}
Arrays.sort(actualResult[]);

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.time.LocalDateTime;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
public class SortNumberFromFile {
public static void main(String[] args) throws IOException {
BufferedReader br = null;
try {
System.out.println("Started at " + LocalDateTime.now());
br = new BufferedReader(new FileReader("/folder/fileName.csv"));//Read data from file named /folder/fileName.csv
List<Long> collect = br.lines().mapToLong(a -> Long.parseLong(a)).boxed().collect(Collectors.toList());//Collect all read data in list object
Collections.sort(collect);//Sort the data
writeRecordsToFile(collect, "/folder/fileName.txt");//Write sorted data to file named /folder/fileName.txt
System.out.println("Ended at " + LocalDateTime.now());
}
finally {
br.close();
}
}
public static <T> void writeRecordsToFile(Collection<? extends T> items, String filePath) {
BufferedWriter writer = null;
File file = new File(filePath);
try {
if(!file.exists()) {
file.getParentFile().mkdirs();
file.createNewFile();
}
writer = new BufferedWriter(new FileWriter(filePath, true));
if(items != null && items.size() > 0) {
for(T eachItem : items) {
if(eachItem != null) {
writer.write(eachItem.toString());
writer.newLine();
}
}
}
} catch (IOException ex) {
}finally {
try {
writer.close();
} catch (IOException e) {
}
}
}
}

file reading into array

I am trying to read contents of a file using string tokenizer and store all the tokens in an array but i keep getting exception in main error. I need advise on how to do this.Below is the code am using for that;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.StringTokenizer;
public class FileTokenizer
{
private static final String DEFAULT_DELIMITERS = "< , { } >";
private static final String DEFAULT_TEST_FILE = "trans1.txt";
public List<String> tokenize(Reader reader) throws IOException
{
List<String> tokens = new ArrayList<String>();
BufferedReader br = null;
try
{
int i = 0;
br = new BufferedReader(reader);
Scanner scanner = new Scanner(br);
while (scanner.hasNext())
{
StringTokenizer st = new StringTokenizer(scanner.next(), DEFAULT_DELIMITERS, true);
while (st.hasMoreElements())
{
String[] t = new String[200];
tokens.add(st.nextToken());
t[i] = st.nextToken();
System.out.println(t[i]);
i++;
}
}
}
finally
{
close(br);
}
return tokens;
}
public static void close(Reader r)
{
try
{
if (r != null)
{
r.close();
}
}
catch (IOException e)
{
e.printStackTrace();
}
}
public static void main(String[] args)
{
try
{
String fileName = ((args.length > 0) ? args[0] : DEFAULT_TEST_FILE);
FileReader fileReader = new FileReader(new File(fileName));
FileTokenizer fileTokenizer = new FileTokenizer();
List<String> tokens = fileTokenizer.tokenize(fileReader);
//System.out.println(tokens);
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
My file looks like;
PDA = (
{ q1, q2, q3, q4},
{ 0, 1 },
{ 0, $ },
{ (q1, #, #) -> { (q2, $) }, (q2, 0, #) -> { (q2, 0) },
(q2, 1, 0) -> { (q3, #) }, (q3, 1, 0) -> { (q3, #) },
(q3, #, $) -> { (q4, #) } },
q1,
{ q1, q4}
)

You will get the java.util.NoSuchElementException since you are calling st.nextToken() twice within the loop
while (st.hasMoreElements())
Modifying harigm's example, you can then add t[i] to tokens as you require
String[] t = new String[200];
System.out.println(t[i]);
tokens.add(t[i]);

Delimiters shouldn't be separated by spaces:
private static final String DEFAULT_DELIMITERS = "<,{}>";
Also, keep the following in mind (from the Javadoc):
StringTokenizer is a legacy class that is retained for compatibility reasons although its use is discouraged in new code. It is recommended that anyone seeking this functionality use the split method of String or the java.util.regex package instead.
String.split() was introduced in JDK 1.4.
That said:
Using a Scanner to tokenize a stream together with a StringTokenizer looks a bit weird to me;
You call st.nextToken() twice in the inner loop;
t is useless. You re-create it each time in your inner loop and use only one element of it.
It seems that what you are trying to build is a lexical analyzer. Maybe you should look up some documentation on the subject.

HI,
I have modified your code and Now works perfectly fine, check this
package org.sample;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.StringTokenizer;
public class FileTokenizer
{
private static final String DEFAULT_DELIMITERS = "< , { } >";
// private static final String DEFAULT_TEST_FILE = "trans1.txt";
public List<String> tokenize(Reader reader) throws IOException
{
List<String> tokens = new ArrayList<String>();
BufferedReader br = null;
try
{
int i = 0;
br = new BufferedReader(reader);
Scanner scanner = new Scanner(br);
while (scanner.hasNext())
{
StringTokenizer st = new StringTokenizer(scanner.next(), DEFAULT_DELIMITERS, true);
while (st.hasMoreElements())
{
String[] t = new String[200];
// tokens.add(st.nextToken());
// t[i] = st.nextToken();
System.out.println(t[i]);
i++;
}
}
}
finally
{
close(br);
}
return tokens;
}
public static void close(Reader r)
{
try
{
if (r != null)
{
r.close();
}
}
catch (IOException e)
{
e.printStackTrace();
}
}
public static void main(String[] args)
{
try
{
// String fileName = ((args.length > 0) ? args[0] : DEFAULT_TEST_FILE);
FileReader fileReader = new FileReader(new File("c:\\DevTest\\1.txt"));
FileTokenizer fileTokenizer = new FileTokenizer();
List<String> tokens = fileTokenizer.tokenize(fileReader);
//System.out.println(tokens);
}
catch (IOException e)
{
e.printStackTrace();
}
}
}

Looking at your input file, I should point out that its hierarchical and irregular structure makes it more suited to be parsed by an actual parser. You may have to learn how to use a parser generator and write a lexer and grammar for it etc, but in the end you'll end up with a much more maintainable code. Doing this yourself is rather painstaking and error-prone.
I recommend ANTLR. It's quite mature, and it has a wide enough user base that I'm sure you can get help easily.