Checking the elements of a set for multiple integers - java

I want to change the form of a given graph. The graph is in the form userID, number of followers, follower1, follower2, ..followerN, delimiter '---', userID2, ...etc.
I have to replace the followers with place values from a second file of the form
ID1 place1
ID2 place2
....
by matching the IDs.
Thus, I want to check if the followers id each time exists in a set.
Both my graph and the set where I seek for the follower ids are huge.
Is there a more efficient way than the one I give you below?
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.util.*;
public class Changer {
public static void main(String[] args) {
Set set = new HashSet();
int[][] users=new int[61578415][];
try{
FileInputStream fstream2 = new FileInputStream(args[0]);
DataInputStream in2 = new DataInputStream(fstream2);
BufferedReader br2 = new BufferedReader(new InputStreamReader(in2));
String strLine2;
while ((strLine2 = br2.readLine()) != null) {
set.add(strLine2);
}
in2.close();
fstream2.close();}
catch (Exception e){
System.err.println("Error: " + e.getMessage()+"!\n"+e.toString()+"!\n");
e.printStackTrace();
System.exit(-1);
}
try{
FileInputStream fstream = new FileInputStream("InputGraph.txt");
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
int flag=0;
int pos=0;
FileWriter fstream3 = new FileWriter("OutputGraph.txt");
BufferedWriter out = new BufferedWriter(fstream3);
int currentUser=0,counter=0;
int theNum=0;
while ((strLine = br.readLine()) != null) {
if(strLine.equals("---")){
if(counter!=pos){
System.out.println("Error reading graph");
System.out.println("For:"+currentUser);
System.exit(-1);
}
flag=0;
pos=0;
continue;
}
theNum=Integer.parseInt(strLine);
if (flag==0){
out.write("---"+"\n");
out.write(""+theNum);
out.write("\n");
currentUser=theNum;
flag+=1;
}
else if (flag==1){
counter=theNum;
users[currentUser]=new int [counter];
flag+=1;
out.write(""+theNum+"\n");
}
else{
users[currentUser][pos]=theNum;
++pos;
Iterator it = set.iterator();
while (it.hasNext()) {
Object element = it.next();
String[] arr = (String.valueOf(element)).split(" ");
if (Integer.parseInt(arr[0])==theNum)
{theNum=Integer.parseInt(arr[1]);break;}
}
out.write(""+theNum);
out.write("\n");
}
}
in.close();
out.close();
}catch (Exception e){
System.err.println("Error: " + e.getMessage());
}
System.out.println("Graph has been read");
System.gc();
System.gc();
System.out.println("Finished");
}
}

It would be more efficient to do the for loop over intersection inside, so that you don't split and parse so much:
Iterator it = set.iterator();
while (it.hasNext()) {
Object element = it.next();
String[] arr = (String.valueOf(element)).split(" ");
int arr0 = Integer.parseInt(arr[0]);
int arr1 = Integer.parseInt(arr[1]);
for (int integer : intersection) {
if (arr0 == integer) {
out.write(integer + " " + arr1 + "\n");
}
}
}
But this changes the order the write will be called in.
However I suspect you might benefit from loading it in to (or just replacing with) a HashMap or SparseArray. It's just hard to tell give then info you have given.

For Integer detection, you can use the comparation with instanceof , but you must use objects and not primitives, e.g:
Integer a=Integer.parseInt("12345");
if(a instanceof Integer){
System.out.println("We have an integer !");
}
Another way for Integer detection is to override the equals method.

Related

Remove duplicate strings from an arraylist<Object>

My program is opening a file and then saves its words and their byte distance from the file beginning . Though the file has too many duplicate words that i don't want . Also i want my list to be in alphabetical order . The problem is that when i fix the order the duplicate are messed and vice versa . Here is my code:
import java.io.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;
class MyMain {
public static void main(String[] args) throws IOException {
ArrayList<DictPage> listOfWords = new ArrayList<DictPage>();
LinkedList<Page> Eurethrio = new LinkedList<Page>();
File file = new File("C:\\Kennedy.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
//This will reference one line at a time...
String line = null;
int line_count=0;
int byte_count;
int total_byte_count=0;
int fromIndex;
int kat = 0;
while( (line = br.readLine())!= null ){
line_count++;
fromIndex=0;
String [] tokens = line.split(",\\s+|\\s*\\\"\\s*|\\s+|\\.\\s*|\\s*\\:\\s*");
String line_rest=line;
for (int i=1; i <= tokens.length; i++) {
byte_count = line_rest.indexOf(tokens[i-1]);
//if ( tokens[i-1].length() != 0)
//System.out.println("\n(line:" + line_count + ", word:" + i + ", start_byte:" + (total_byte_count + fromIndex) + "' word_length:" + tokens[i-1].length() + ") = " + tokens[i-1]);
fromIndex = fromIndex + byte_count + 1 + tokens[i-1].length();
if (fromIndex < line.length())
line_rest = line.substring(fromIndex);
if(!listOfWords.contains(tokens[i-1])){//Na mhn apothikevetai h idia leksh
//listOfWords.add(tokens[i-1]);
listOfWords.add(new DictPage(tokens[i-1],kat));
kat++;
}
Eurethrio.add(new Page("Kennedy",fromIndex));
}
total_byte_count += fromIndex;
Eurethrio.add(new Page("Kennedy", total_byte_count));
}
Set<DictPage> hs = new HashSet<DictPage>();
hs.addAll(listOfWords);
listOfWords.clear();
listOfWords.addAll(hs);
if (listOfWords.size() > 0) {
Collections.sort(listOfWords, new Comparator<DictPage>() {
#Override
public int compare(final DictPage object1, final DictPage object2) {
return object1.getWord().compareTo(object2.getWord());
}
} );
}
//Ektypwsh leksewn...
for (int i = 0; i<listOfWords.size();i++){
System.out.println(""+listOfWords.get(i).getWord()+" "+listOfWords.get(i).getPage());
}
for (int i = 0;i<Eurethrio.size();i++){
System.out.println(""+Eurethrio.get(i).getFile()+" "+Eurethrio.get(i).getBytes());
}
}
}
Use the TreeSet instead of ArrayList, and you'll get automatically order and no repeatings.
In the first place, why are you using ArrayList to store your list of words.
ArrayList<DictPage> listOfWords = new ArrayList<DictPage>();
You should use Set (like HashSet, TreeSet or some implementation of Set) to store your words if you don't want duplicates.
Set<DictPage> listOfWords = new Hashset<DictPage>(); //no duplicates but not sorted
Or
Set<DictPage> listOfWords = new Treeset<DictPage>(); //no duplicates and sorted as well
This would make sure that your list of words does not contain any duplicates.
And if you want them sorted straight away, you can use TreeSet which will make it more easier for you.
use this.
public void stripDuplicatesFromFile(String filename) {
try {
BufferedReader reader = new BufferedReader(new FileReader(filename));
Set<String> lines = new HashSet<String>();
String line;
while ((line = reader.readLine()) != null) {
lines.add(line);
}
reader.close();
BufferedWriter writer = new BufferedWriter(new FileWriter(filename));
for (String unique : lines) {
writer.write(unique);
writer.newLine();
}
writer.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
it takes filepath as an input, find duplicate lines and remove them. But if you have large file do not use this. I'm using this method on a very small size of a .txt file (kind of log file and order is not imported).

Sorting .csv Id's in natural order Java

I'm trying to write some code that will take in a list of IDs (numbers and letters) from a .csv file and output them to a new file with the IDs in "natural order". My files are compiling, but I am getting the error:
java.lang.NumberFormatException: For input string: "Alpha"
I think the issue is I am not accounting for both number and letter values in the .csv file. What am I doing wrong?! Sorry if my variable Id's are confusing...
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
public class IdReader {
public static String CSV_FILE_PATH = "/Users/eringray/Desktop/idreader/idData.csv";
public static void main(String[] args){
try {
BufferedReader br = new BufferedReader(new FileReader(CSV_FILE_PATH));
BufferedWriter bw = new BufferedWriter(new FileWriter(CSV_FILE_PATH + ".tsv"));
ArrayList<String> textIds = new ArrayList<>();
ArrayList<Integer> numberIds = new ArrayList<>();
String line = "";
while((line = br.readLine()) != null) {
String[] values = line.split(" ");
if(values.length == 1) {
String idAsString = values[0];
try{
int id = Integer.parseInt(idAsString);
numberIds.add(id);
}
catch(NumberFormatException e){
textIds.add(idAsString);
}
}
}
Collections.sort(textIds);
Collections.sort(numberIds);
for(int i = 0; i < textIds.size(); i++){
String stu = textIds.get(i);
String lineText = stu.toString();
bw.write(lineText);
bw.newLine();
}
for(int i = 0; i < numberIds.size(); i++){
int numValues = numberIds.get(i);
bw.write(numValues);
bw.newLine();
}
br.close();
bw.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
The exception is coming at this line
int id = Integer.parseInt(idAsString);
Clearly alpha is not an integer, so it will throw NumberFormatException. In a case, where you encounter such Strings which cannot be converted into numbers, you can either skips them or throw an exception.
Update
//Use two seperate lists, one for maintaining numbers and other for text
ArrayList<String> textIds = new ArrayList<>();
ArrayList<Integer> numberIds = new ArrayList<>();
String line = "";
while((line = br.readLine()) != null) {
String[] values = line.split(" ");
if(values.length == 1) {
String idAsString = values[0];
try {
//Parse the value. If successful, it means it was a number. Add to integer array.
int id = Integer.parseInt(idAsString);
numberIds.add(id);
}catch (NumberFormatException e){
//If not successful, it means it was a string.
textIds.add(idAsString);
}
}
}
//In the end sort both the list
Collections.sort(textIds);
Collections.synchronizedList(numberIds);
for(int i = 0; i < textIds.size(); i++){
String stu = textIds.get(i);
bw.write(stu);
bw.newLine();
}
for(int i = 0; i < numberIds.size(); i++){
int numValues = numberIds.get(i);
bw.write(numValues+"");
bw.newLine();
}
br.close();
bw.close();
I am not putting code for writing this data to a new file. I hope you can do that.
Sample Input
4
6
33
2
5632
23454
Alpha
So after running my code
numberIds will have [ 2,4,6,33,5632,23454]
textIds will have ["Alpha"]
NumberFormatException occurs because of AlphaNumeric characters in the input.
Please use isNumeric(str) metod in https://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/StringUtils.html api to verify whether the input is numeric or not and convert to int , only it is numeric

Read a file into Map<Integer, ArrayList<Double>>

I saw some similar questions, but mine is a little different.
I define a
Map<Integer, ArrayList<Double>> fl;
My input .txt file:
1 0.56 0.57 0.73 ..
2 2.3 3.50 ...
9 4.98 0.99 ..
How to read the file into the map fl?
Thanks!
Use a Scanner and first call Scanner.readInt() that will give you the first integer.
Then call Scanner.readLine() that will give you all the remaining double in the line as a String. Split it and parse everything to double.
Repeat the same till end of file.
Here's a try.
I've compiled and run the code.
Make sure the input file is in the same directory as your project if you use an IDE.-- This only applies if you do not modify the path below.
package fileread;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
public class FileRead {
private static HashMap<Integer, ArrayList<Double>> map = new HashMap<>();
private static BufferedReader reader;
public static void main(String[] args) {
try
{
reader = new BufferedReader(new FileReader("input"));
//or reader = new BufferedReader(new FileReader("C:\\full-path-to-your-file));
String line;
while((line = reader.readLine()) != null)
{
String[] tokens = line.split(" ");
Integer i;
Double d;
ArrayList<Double> list = new ArrayList<>();
i = Integer.valueOf(tokens[0]);
for(int j = 1; j < tokens.length; j++)
list.add(Double.valueOf(tokens[j]));
map.put(i, list);
}
}catch(IOException ex)
{
//break execution
}finally
{
if(reader != null)
try
{
reader.close();
}catch (IOException ex) {
//don't break :)
}
}
for(Integer i : map.keySet())
{
ArrayList<Double> l = map.get(i);
System.out.print("Line " + i + ": ");
for(Double d: l)
System.out.print(d + " ");
System.out.println();
}
}
}
The code for parsing the file and populating the map should be like below
try {
BufferedReader bReader = new BufferedReader(new FileReader(new File("c:/input .txt")));
String line = "";
Map<Integer, ArrayList<Double>> fl = new HashMap<Integer, ArrayList<Double>>();
while ((line = bReader.readLine()) != null) {
String[] strArray = line.split(" ");
for (int i=0;i<strArray.length;i++) {
ArrayList<Double> value = new ArrayList<Double>();
int key=0;
if(i==0){
key =Integer.valueOf(strArray[0]);
}
else{
value.add(Double.valueOf(strArray[i]));
}
fl.put(key, value);
}
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

JAVA : file I/O

I have got two text files with data in the following format
data.txt file as following format
A 10
B 20
C 15
data1.txt file is in format (start node,end node, distance):
A B 5
A C 10
B C 20
I am trying to implement a search strategy, for that I need to load the data from data.txt and ONLY the start node and end node from data1.txt (i.e. I dont need the distance). I need to store this information in a stack as I think it would be a best data structure for implementing greedy search.
Actually I am not sure how to get started with file I/O to read these files and store them in array to implement greedy search. So I would highly appreciate any starting idea on how to proceed.
I am new to this, so please bear with me. Any help is much appreciated. Thanks.
EDIT:
Here is what I have got till now
String heuristic_file = "data.txt";
try
{
FileReader inputHeuristic = new FileReader(heuristic_file);
BufferedReader bufferReader = new BufferedReader(inputHeuristic);
String line;
while ((line = bufferReader.readLine()) != null)
{
System.out.println(line);
}
bufferReader.close();
} catch(Exception e) {
System.out.println("Error reading file " + e.getMessage());
}
My approach, doesn't differ fundamentally from the others. Please regard the try/catch/finally blocks. Always put the closing statements into the finally block, so the opened file is guaranteed to be closed, even if an exception was thrown while reading the file.
The part between the two //[...] could surely be done more efficient. Maybe reading the whole file in one take and then parsing the text backwards and searching for a line-break? Maybe a Stream-API supports to set the reading position. I honestly don't know. I didn't need that, up to now.
I chose to use the verbose initialization of the BufferedReader, because then you can specify the expected encoding of the file. In your case it doesn't matter, since your files do not contain symbols out of the standard ASCII range, but I believe it's a semi-best-practice.
Before you ask: r.close() takes care of closing the underlying InputStreamReader and FileInputStream in the right order, till all readers and streams are closed.
public static void readDataFile(String dir, String file1, String file2)
throws IOException
{
File datafile1 = new File(dir, file1);
File datafile2 = new File(dir, file2);
if (datafile1.exists())
{
BufferedReader r = null;
try
{
r = new BufferedReader(
new InputStreamReader(
new FileInputStream(datafile1),
"UTF-8"
)
);
String row;
Stack<Object[]> s = new Stack<Object[]>();
String[] pair;
Integer datapoint;
while((row = r.readLine()) != null)
{
if (row != null && row.trim().length() > 0)
{
// You could use " " instead of "\\s"
// but the latter regular expression
// shorthand-character-class will
// split the row on tab-symbols, too
pair = row.split("\\s");
if (pair != null && pair.length == 2)
{
datapoint = null;
try
{
datapoint = Integer.parseInt(pair[1], 10);
}
catch(NumberFormatException f) { }
// Later you can validate datapairs
// by using
// if (s.pop()[1] != null)
s.add(new Object[] { pair[0], datapoint});
}
}
}
}
catch (UnsupportedEncodingException e1) { }
catch (FileNotFoundException e2) { }
catch (IOException e3) { }
finally
{
if (r != null) r.close();
}
}
// Do something similar with datafile2
if (datafile2.exists())
{
// [...do the same as in the first try/catch block...]
String firstrow = null, lastrow = null;
String row = null;
int i = 0;
do
{
lastrow = row;
row = r.readLine();
if (i == 0)
firstrow = row;
i++;
} while(row != null);
// [...parse firstrow and lastrow into a datastructure...]
}
}
use split
while ((line = bufferReader.readLine()) != null)
{
String[] tokens = line.split(" ");
System.out.println(line + " -> [" + tokens[0] + "]" + "[" + tokens[1] + "][" + tokens[2] + "]");
}
if you must have this in an array you can use the following:
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;
public class NodeTest {
public static void main(String[] args) throws ParseException {
try {
File first = new File("data.txt");
File second = new File("data1.txt");
Node[] nodes1 = getNodes(first);
Node[] nodes2 = getNodes(second);
print(nodes1);
print(nodes2);
}
catch(Exception e) {
System.out.println("Error reading file " + e.getMessage());
}
}
public static final void print(Node[] nodes) {
System.out.println("======================");
for(Node node : nodes) {
System.out.println(node);
}
System.out.println("======================");
}
public static final Node[] getNodes(File file) throws IOException {
FileReader inputHeuristic = new FileReader(file);
BufferedReader bufferReader = new BufferedReader(inputHeuristic);
String line;
List<Node> list = new ArrayList<Node>();
while ((line = bufferReader.readLine()) != null) {
String[] tokens = line.split(" ");
list.add(new Node(tokens[0], tokens[1]));
}
bufferReader.close();
return list.toArray(new Node[list.size()]);
}
}
class Node {
String start;
String end;
public Node(String start, String end){
this.start = start;
this.end = end;
}
public String toString() {
return "[" + start + "][" + end + "]";
}
}
Something like this?
HashSet<String> nodes = new HashSet<String>();
try(BufferedReader br = new BufferedReader(new FileReader("data.txt"))) {
String line = br.readLine();
while (line != null) {
String[] l = line.split(" ");
nodes.add(l[0]);
line = br.readLine();
}
}
try(BufferedReader br = new BufferedReader(new FileReader("data1.txt"))) {
String line = br.readLine();
while (line != null) {
String[] l = line.split(" ");
if (nodes.contains(l[0]) || nodes.contains(l[1]))
// Do whatever you want ...
line = br.readLine();
}
}

Reading text file in java

Here I'm trying to read a text file which contains only integers.in every line.For eg:
1
2
3
1
I wrote the following code to read the text file. Code as shown below.
package fileread;
import java.io.*;
public class Main {
public static void main(String[] args) {
// TODO code application logic here
try{
FileInputStream fstream=new FileInputStream("C:/Users/kiran/Desktop/text.txt");
DataInputStream in=new DataInputStream (fstream);
BufferedReader br=new BufferedReader(new InputStreamReader(in));
String str;
while((str=br.readLine())!=null){
System.out.println(str);
}
in.close();
}
catch(Exception e){
System.err.println(e);
}
}
}
Now I want to retrieve only those integers which repeated and display it to the user.
In this case i want to display "1".
How can I implement this in Java??
package fileread;
import java.io.*;
import java.util.HashSet;
import java.util.Set;
public class Main {
public static void main(String[] args) {
Set<String> uniqueLines = new HashSet<String>();
Set<String> duplicatedLines = new HashSet<String>();
try{
FileInputStream fstream=new FileInputStream("C:/Users/kiran/Desktop/text.txt");
DataInputStream in=new DataInputStream (fstream);
BufferedReader br=new BufferedReader(new InputStreamReader(in));
String str;
while((str=br.readLine())!=null){
if (uniqueLines.contains(str)) {
if (!duplicatedLines.contains(str)) {
duplicatedLines.add(str);
System.out.println(str);
}
} else {
uniqueLines.add(str);
}
}
in.close();
}
catch(Exception e){
System.err.println(e);
}
}
}
Note: Make sure your input doesn't have trailing whitespace on each line. Also, note that when the list gets long, this implementation is not particularly memory friendly.
You need to read the value in an array and then find duplicate entries in that array.
Read the file entirely, save the lines to a data structure of your choice (map(key=line, value=count), array if only integers), enumerate the data structure and print these whose value is greater than 1 (if the value represents the count).
or on the fly: read the file, add entry to a set/list/array, if not contained in set/list/array, else print out line.
Well, you can use an array with 10 slots which maps to a number from 0 to 9. For every line, you check what that number is and increment the value in the array accordingly. It would be something like this:
// Initialize the array
int[] numberArray = new int[10];
for (int i = 0 ; i < 10 ; i++) numberArray[i] = 0;
while((str=br.readLine())!=null){
int number = Integer.parseInt(str);
numberArray[number]++;
}
for (int i = 0 ; i < 10 ; i++) {\
if (numberArray[i] > 1) System.out.println(i);
}
In addition to the given answers, make sure you are converting your strings to integers (numbers) and catch the exception in case whatever comes from the file isn't a number. In this case I think you can safely ignore the exception because it's not relevant, but it's a good practice to check your input data.
First off, I would define 1 list and 1 set of Integers, as below:
ArrayList<Integer> intList = new ArrayList<Integer>();
Set<Integer> duplicateIntSet = new HashSet<Integer>(); //Set is used to avoid duplicates
And then, I would check for duplicates and add 'em to respective lists, as below:
while((str=br.readLine())!=null){
if(!str.isEmpty()) {
Integer i = Integer.parseInt(str);
if(intList.contains(i)) {
duplicateIntSet.add(i);
} else {
intList.add(i);
}
}
}
Something like this
package fileread;
import java.io.*;
import java.util.*;
public class Main {
public static void main(String[] args) {
Hashtable ht = new Hashtable();
try{
FileInputStream fstream =
new FileInputStream("C:/Users/kiran/Desktop/text.txt");
DataInputStream in=new DataInputStream (fstream);
BufferedReader br=new BufferedReader(new InputStreamReader(in));
String str;
while((str=br.readLine())!=null){
String sproof = (String) ht.get(str.trim());
if (sproof != null && sproof.equals("1")) {
System.out.println(str);
} else {
ht.put(str.trim(), "1");
}
}
in.close();
}
catch(Exception e){
System.err.println(e);
}
}
}
I would use the two set approach;
public static void main(String[] args) {
Set<Integer> result = new HashSet<Integer>();
Set<Integer> temp = new HashSet<Integer>();
try{
FileInputStream fstream=new FileInputStream("text.txt");
DataInputStream in=new DataInputStream (fstream);
BufferedReader br=new BufferedReader(new InputStreamReader(in));
String str;
while((str=br.readLine())!=null){
if (!"".equals(str.trim())){
try {
Integer strInt = new Integer(str.trim());
if(temp.contains(strInt)){
result.add(strInt);
} else {
temp.add(strInt);
}
} catch (Exception e){
// usually NumberFormatException
System.err.println(e);
}
}
}
in.close();
}
catch(Exception e){
System.err.println(e);
}
for(Integer resultVal : result){
System.out.println(resultVal);
}
}
Alternately, you could also use a single HashMap with the HashMap.Key as the Integer and the HashMap.Value as count for that Integer.
Then if you later need to refactor to find all instances with a single occurrence then you can easily do that.
public static void main(String[] args) {
Map<Integer, Integer> frequency = new HashMap<Integer, Integer>();
try{
FileInputStream fstream=new FileInputStream("text.txt");
DataInputStream in=new DataInputStream (fstream);
BufferedReader br=new BufferedReader(new InputStreamReader(in));
String str;
while((str=br.readLine())!=null){
if (!"".equals(str.trim())){
try {
Integer strInt = new Integer(str.trim());
int val = 1;
if(frequency.containsKey(strInt)){
val = frequency.get(strInt).intValue() + 1;
}
frequency.put(strInt, val);
} catch (Exception e){
// usually NumberFormatException
System.err.println(e);
}
}
}
in.close();
}
catch(Exception e){
System.err.println(e);
}
// this is your method for more than 1
for(Integer key : frequency.keySet()){
if (frequency.get(key).intValue() > 1){
System.out.println(key);
}
}
// This shows the frequency of values in the file.
for(Integer key : frequency.keySet()){
System.out.println(String.format("Value: %s, Freq: %s", key, frequency.get(key)));
}
}
Be careful of NumberFormatExceptions, and depending on your situation, you can either handle them inside the loop, or outside the loop.

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