Develop Reference

Indexing through an array to return any specific value in java

So, I have created code which is reading a CSV file line by line, then splitting each line into their individual values then putting this into an array, but i am stuck on trying the index a value from this array I have created, I will attach the CSV file and also my code, and lets say for example how would I access the value at [3,4], which should be Andorra, and [6,6] which should be 17?
CSV FILE:
Date,iso3,Continent,CountryName,lat,lon,CumulativePositive,CumulativeDeceased,CumulativeRecovered,CurrentlyPositive,Hospitalized,IntensiveCare,NUTS
31/1/2021,AFG,AS,Afghanistan,33.930445,67.678945,55023,2400,,52623,,,AF
31/1/2021,ALB,EU,Albania,41.156986,20.181222,78127,1380,47424,29323,324,19,AL
31/1/2021,DZA,AF,Algeria,28.026875,1.65284,107122,2888,,104234,,,DZ
31/1/2021,AND,EU,Andorra,42.542268,1.596865,9937,101,,9836,44,,AD
31/1/2021,AGO,AF,Angola,-11.209451,17.880669,19782,464,,19318,,,AO
31/1/2021,AIA,NA,Anguilla,18.225119,-63.07213,17,0,,17,,,AI
31/1/2021,ATG,NA,Antigua and Barbuda,17.363183,-61.789423,218,7,,211,,,AG
31/1/2021,ARG,SA,Argentina,-38.421295,-63.587403,1915362,47775,,1867587,,,AR
31/1/2021,ARM,AS,Armenia,40.066181,45.111108,167026,3080,,163946,,,AM
31/1/2021,ABW,NA,Aruba,12.517713,-69.965112,6858,58,,6800,,,AW
31/1/2021,AUS,OC,Australia,-26.853388,133.275154,28806,909,,27897,,,AU
31/1/2021,AUT,EU,Austria,47.697542,13.349319,411921,7850,383158,21058,1387,297,AT
31/1/2021,AZE,AS,Azerbaijan,40.147396,47.572098,229935,3119,,226816,,,AZ
31/1/2021,BHS,NA,Bahamas,24.885993,-76.709892,8174,176,,7998,,,BS
31/1/2021,BHR,AS,Bahrain,26.039722,50.559306,102626,372,,102254,,,BH
31/1/2021,BGD,AS,Bangladesh,23.68764,90.351002,535139,8127,,527012,,,BD
31/1/2021,BRB,NA,Barbados,13.18355,-59.534649,1498,12,,1486,,,BB
31/1/2021,BLR,EU,Belarus,53.711111,27.973847,248336,1718,,246618,,,BY
31/1/2021,BEL,EU,Belgium,50.499527,4.475402,711417,21118,,690299,1788,315,BE
31/1/2021,BLZ,NA,Belize,17.192929,-88.5009,11877,301,,11576,,,BZ
31/1/2021,BEN,AF,Benin,9.322048,2.313138,3786,48,,3738,,,BJ
31/1/2021,BMU,NA,Bermuda,32.320236,-64.774022,691,12,,679,,,BM
31/1/2021,BTN,AS,Bhutan,27.515709,90.442455,859,1,,858,,,BT
31/1/2021,BWA,AF,Botswana,-22.344029,24.680158,21293,134,,21159,,,BW
31/1/2021,BRA,SA,Brazil,-14.242915,-53.189267,9118513,222666,,8895847,,,BR
31/1/2021,VGB,NA,British Virgin Islands,18.573601,-64.492065,141,1,,140,,,VG
CODE:
public static String readFile(String file) {
FileInputStream fileStream = null;
InputStreamReader isr;
BufferedReader bufRdr;
int lineNum;
String line = null;
try {
fileStream = new FileInputStream(file);
isr = new InputStreamReader(fileStream);
bufRdr = new BufferedReader(isr);
lineNum = 0;
line = bufRdr.readLine();
while ((line != null) && lineNum < 27) {
lineNum++;
System.out.println(line);
line = bufRdr.readLine();
}
fileStream.close();
}
catch (IOException e) {
if (fileStream != null) {
try {
fileStream.close();
}
catch (IOException ex2) {
}
}
System.out.println("Error: " + e.getMessage());
}
return line;
}
private static void processLine(String line) {
String[] splitLine;
splitLine = line.split(",");
int lineLength = splitLine.length;
for (int i = 0; i < lineLength; i++) {
System.out.print(splitLine[i] + " ");
}
System.out.println("");
}

You need to create a 2D array in readFile. As the file is read, and and each line is split by processLine, insert the array into the 2D array. The method readFile at the end returns the 2D array. Make processLine to return a string array and have it return the result of the split.
I marked where I made changes to your code.
import java.io.*;
public class Main
{
public static void main(String[] args){
String[][] data = readFile("data.txt");
System.out.println(data[3][4]);
System.out.println(data[6][6]);
}
public static String[][] readFile(String file) { //<<< changed
FileInputStream fileStream = null;
InputStreamReader isr;
BufferedReader bufRdr;
int lineNum;
String line = null;
String[][] data = new String[28][]; //<<< added
try {
fileStream = new FileInputStream(file);
isr = new InputStreamReader(fileStream);
bufRdr = new BufferedReader(isr);
lineNum = 0;
line = bufRdr.readLine();
while (lineNum < 27) { // <<< changed
System.out.println(line);
line = bufRdr.readLine();
if (line == null) break; // <<< added
data[lineNum++] = processLine(line); // <<< added
}
fileStream.close();
}
catch (IOException e) {
if (fileStream != null) {
try {
fileStream.close();
}
catch (IOException ex2) {
}
}
System.out.println("Error: " + e.getMessage());
}
return data; //added
}
private static String[] processLine(String line) { //<< changed
String[] splitLine;
splitLine = line.split(",");
int lineLength = splitLine.length;
for (int i = 0; i < lineLength; i++) {
System.out.print(splitLine[i] + " ");
}
System.out.println("");
return splitLine; // <<< added
}
}

You can do it quite simply using the stream API.
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class CsvTest0 {
public static void main(String[] args) {
Path path = Paths.get("geografy.csv");
try (Stream<String> lines = Files.lines(path)) {
String[][] arr = lines.skip(1L)
.limit(27L)
.map(l -> l.split(","))
.collect(Collectors.toList())
.toArray(new String[][]{});
System.out.println(arr[3][3]);
System.out.println(arr[5][6]);
}
catch (IOException xIo) {
xIo.printStackTrace();
}
}
}
However, regarding the code in your question, below is a fixed version followed by notes and explanations.
import java.io.BufferedReader;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class CsvTest1 {
public static String[][] readFile(String file) throws IOException {
Path path = Paths.get(file);
String[][] arr = new String[27][];
int lineNum;
String line = null;
try (BufferedReader bufRdr = Files.newBufferedReader(path)) {
lineNum = 0;
line = bufRdr.readLine(); // Ignore first line of file since it contains headings only.
line = bufRdr.readLine();
while ((line != null) && lineNum < 27) {
arr[lineNum++] = processLine(line);
line = bufRdr.readLine();
}
}
return arr;
}
private static String[] processLine(String line) {
return line.split(",");
}
public static void main(String[] args) {
try {
String[][] arr = readFile("geografy.csv");
System.out.println(arr[3][3]);
System.out.println(arr[5][6]);
}
catch (IOException x) {
x.printStackTrace();
}
}
}
Note that the below is not in any particular order. I wrote them as they came to me.
No need for FileInputStream and InputStreamReader in order to create BufferedReader. Use Files class instead.
Close files in a finally block and not in a catch block. Hence use try-with-resources.
I believe better to propagate the exception to the calling method, i.e. method main in this case. I also believe that, unless you can safely ignore the exception, it is always beneficial to print the stack trace.
You don't want to process the first line of the file.
You appear to have your array indexes mixed up. According to sample data, Andorra is row 3 and column 3 (not column 4). Also, 17 is at [5][6] and not [6][6].
Two-dimensional arrays in java can be declared with only one dimension indicated. Since you only want first 27 lines of file, you know how many rows will be in the 2D array.

Reading character files between specific word in java

I have a java file, FileJava.java like this:
public class FileJava {
public static void main(String args[]) {
for (int i = 0; i < 5; i++) {
}
}
}
Then, i read above code line by line using this code:
import java.util.List;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;
public class FileReplace {
List<String> lines = new ArrayList<String>();
String line = null;
public void doIt() {
try {
File f1 = new File("FileJava.java");
FileReader fr = new FileReader(f1);
BufferedReader br = new BufferedReader(fr);
while ((line = br.readLine()) != null) {
if (line.contains("for"))
{
lines.add("long A=0;");
if(line.contains("(") && line.contains(")")){
String get = line;
String[] split = get.split(";");
String s1 = split[0];
String s2 = split[1];
String s3 = split[2];
}
}
lines.add(line);
}
fr.close();
br.close();
FileWriter fw = new FileWriter(f1);
BufferedWriter out = new BufferedWriter(fw);
for(String s : lines)
out.write(s);
out.flush();
out.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
public static void main(String args[]) {
FileReplace fr = new FileReplace();
fr.doIt();
}
}
The question is, how to read character between '(' and ')' inside (for) in the FileJava.java, the character i mean "int i = 0; i < 5; i++" that will be stored in a variable, i have split based on ";", but when i print, the value :
s1 = for (int i = 0
s2 = i < 5
s3 = i++) {
While i expect:
s1 = int i = 0
s2 = i < 5
s3 = i++
Thanks

To answer your question how to restrict the splitting to the parenthesized section:
String[] split =
get.substring( get.indexOf('(')+1, get.indexOf(')').split("\\s*;\\s*");
Edit to address another prob.
Printing of the file will all happen in one line, because BufferedReader.readLine strips the line ends (LF, CRLF) from the line it returns. Thus, add a line break when writing:
for(String s : lines){
out.write(s);
out.newLine();
}

int index1 = line.indexOf("(");
int index2 = line.indexOf(")");
line = line.subString(index1 + 1, index2);

Its because you are splitting on ';' for the input
for (int i = 0; i < 5; i++) {
which will return all the characters between ';'
You can write a new method, called getBracketContent for example, that will be something like
String getBracketContent(String str)
{
int startIdx = str.indexOf('(')
int endIdx = str.indexOf(')')
String content = str.subString(startIdx + 1, endIdx);
}
then your code would be
if(line.contains("(") && line.contains(")")){
String get = getBracketContent(line);
String[] split = get.split(";");
Ideally I would use regular expressions to parse the information you need, but that is probably something you may want to look into later.

If you want to read the contents of a java file, you would be much better off using an AST (Abstract Syntax Tree) parser which will read in the contents of the file and then callback when it encounters certain expressions. In your case, you can listen just for the 'for' loop.

Reverse lines in ArrayList Java

I'm working on a Java program in which I must read the contents of a file and then print each lines reverse. For example the text:
Public Class Helloprinter
Public static void
would print the following after running my reverse program:
retnirPolleh ssalc cilbup
diov citats cilbup
Here's what I got so far:
public static void main(String[] args) throws FileNotFoundException {
// Prompt for the input and output file names
ArrayList<String> list = new ArrayList<String>();
//String reverse = "";
Scanner console = new Scanner(System.in);
System.out.print("Input file: ");
String inputFileName = console.next();
System.out.print("Output file: ");
String outputFileName = console.next();
// Construct the Scanner and PrintWriter objects for reading and writing
File inputFile = new File(inputFileName);
Scanner in = new Scanner(inputFile);
PrintWriter out = new PrintWriter(outputFileName);
String aString = "";
while(in.hasNextLine())
{
String line = in.nextLine();
list.add(line);
}
in.close();
for(int i = 0; i <list.size(); i++)
{
aString = list.get(i);
aString = new StringBuffer(aString).reverse().toString();
out.printf("%s", " " + aString);
}
out.close();
}
}
EDIT:
With Robert's posting it helped put me in the right direction. The problem is that with that is that it doesn't keep the lines.
Public Class Helloprinter
Public static void
becomes after running my program:
retnirPolleh ssalc cilbup diov citats cilbup
it needs to keep the line layout the same. so it should be:
retnirPolleh ssalc cilbup
diov citats cilbup

Your problem is in the line
out.printf("%s", " " + aString);
This doesn't output a newline. I'm also not sure why you are sticking a space in there.
It should be either:
out.println( aString );
Or
out.printf("%s%n", aString);

In your last loop why don't you just iterate through the list backwards? So:
for(int i = 0; i <list.size(); i++)
Becomes:
for(int i = list.size() - 1; i >=0; i--)

It seems like you already know how to read a file, so then call this method for each line.
Note, this is recursion and it's probably not the most efficient but it's simple and it does what you want.
public String reverseString(final String s) {
if (s.length() == 0)
return s;
// move chahctrachter at current position and then put it at the end of the string.
return reverseString(s.substring(1)) + s.charAt(0);
}

Just use a string builder. You were on the right trail. Probably just needed a little help. There is no "one way" to do anything, but you could try something like this:
Note: Here is my output: retnirPolleh ssalc cilbup diov citats cilbup
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Scanner;
public class Reverse {
public static void main(String[] args) {
ArrayList<String> myReverseList = null;
System.out.println("Input file: \n");
Scanner input = new Scanner(System.in);
String fileName = input.nextLine();
System.out.println("Output file: \n");
String outputFileName = input.nextLine();
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(fileName));
String text = null;
myReverseList = new ArrayList<String>();
StringBuilder sb = null;
try {
while ((text = br.readLine()) != null) {
sb = new StringBuilder();
for (int i = text.length() - 1; i >= 0; i--) {
sb.append(text.charAt(i));
}
myReverseList.add(sb.toString());
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Writer writer = null;
try {
writer = new BufferedWriter(new OutputStreamWriter(
new FileOutputStream(outputFileName), "utf-8"));
for (String s : myReverseList) {
writer.write("" + s + "\n");
}
} catch (IOException ex) {
// report
} finally {
try {
writer.close();
} catch (Exception ex) {
}
}
}
}

Converting CSV File to Java - Copied in Backwards

I previously asked a question about converting a CSV file to 2D array in java. I completely rewrote my code and it is almost reworking. The only problem I am having now is that it is printing backwards. In other words, the columns are printing where the rows should be and vice versa. Here is my code:
int [][] board = new int [25][25];
String line = null;
BufferedReader stream = null;
ArrayList <String> csvData = new ArrayList <String>();
stream = new BufferedReader(new FileReader(fileName));
while ((line = stream.readLine()) != null) {
String[] splitted = line.split(",");
ArrayList<String> dataLine = new ArrayList<String>(splitted.length);
for (String data : splitted)
dataLine.add(data);
csvData.addAll(dataLine);
}
int [] number = new int [csvData.size()];
for(int z = 0; z < csvData.size(); z++)
{
number[z] = Integer.parseInt(csvData.get(z));
}
for(int q = 0; q < number.length; q++)
{
System.out.println(number[q]);
}
for(int i = 0; i< number.length; i++)
{
System.out.println(number[i]);
}
for(int i=0; i<25;i++)
{
for(int j=0;j<25;j++)
{
board[i][j] = number[(j*25) + i];
}
}
Basically, the 2D array is supposed to have 25 rows and 25 columns. When reading the CSV file in, I saved it into a String ArrayList then I converted that into a single dimension int array. Any input would be appreciated. Thanks

so you want to read a CSV file in java , then you might wanna use OPEN CSV
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import au.com.bytecode.opencsv.CSVReader;
public class CsvFileReader {
public static void main(String[] args) {
try {
System.out.println("\n**** readLineByLineExample ****");
String csvFilename = "C:/Users/hussain.a/Desktop/sample.csv";
CSVReader csvReader = new CSVReader(new FileReader(csvFilename));
String[] col = null;
while ((col = csvReader.readNext()) != null)
{
System.out.println(col[0] );
//System.out.println(col[0]);
}
csvReader.close();
}
catch(ArrayIndexOutOfBoundsException ae)
{
System.out.println(ae+" : error here");
}catch (FileNotFoundException e)
{
System.out.println("asd");
e.printStackTrace();
} catch (IOException e) {
System.out.println("");
e.printStackTrace();
}
}
}
and you can get the related jar file from here

Find specific word in text file and count it

someone can help me with code?
How to search in text file any word and count how many it were repeated?
For example test.txt:
hi
hola
hey
hi
bye
hoola
hi
And if I want to know how many times are repeated in test.txt word "Hi" program must say "3 times repeated"
I hope you understood what I want, thank you for answers.

public int countWord(String word, File file) {
int count = 0;
Scanner scanner = new Scanner(file);
while (scanner.hasNextLine()) {
String nextToken = scanner.next();
if (nextToken.equalsIgnoreCase(word))
count++;
}
return count;
}

HashMap h=new HashMap();
FileInputStream fin=new FileInputStream("d:\\file.txt");
BufferedReader br=new BufferedReader(new InputStreamReader(fin));
String n;
while((n=br.readLine())!=null)
{
if(h.containsKey(n))
{
int i=(Integer)h.get(n);
h.put(n,(i+1));
}
else
h.put(n, 1);
}
now iterate through this map to get the count for each word using each word as a key to the map values

Apache Commons - StringUtils.countMatches()

Use MultiSet collection from google guava library.
Multiset<String> wordsMultiset = HashMultiset.create();
Scanner scanner = new Scanner(fileName);
while (scanner.hasNextLine()) {
wordsMultiset.add(scanner.nextLine());
}
for(Multiset.Entry<String> entry : wordsMultiset ){
System.out.println("Word : "+entry.getElement()+" count -> "+entry.getCount());
}

package File1;
import java.io.BufferedReader;
import java.io.FileReader;
public class CountLineWordsDuplicateWords {
public static void main(String[] args) {
FileReader fr = null;
BufferedReader br =null;
String [] stringArray;
int counLine = 0;
int arrayLength ;
String s="";
String stringLine="";
try{
fr = new FileReader("F:/Line.txt");
br = new BufferedReader(fr);
while((s = br.readLine()) != null){
stringLine = stringLine + s;
stringLine = stringLine + " ";/*Add space*/
counLine ++;
}
System.out.println(stringLine);
stringArray = stringLine.split(" ");
arrayLength = stringArray.length;
System.out.println("The number of Words is "+arrayLength);
/*Duplicate String count code */
for (int i = 0; i < arrayLength; i++) {
int c = 1 ;
for (int j = i+1; j < arrayLength; j++) {
if(stringArray[i].equalsIgnoreCase(stringArray[j])){
c++;
for (int j2 = j; j2 < arrayLength; j2++) {
stringArray[j2] = stringArray[j2+1];
arrayLength = arrayLength - 1;
}
}//End of If block
}//End of Inner for block
System.out.println("The "+stringArray[i]+" present "+c+" times .");
}//End of Outer for block
System.out.println("The number of Line is "+counLine);
System.out.println();
fr.close();
br.close();
}catch (Exception e) {
e.printStackTrace();
}
}//End of main() method
}//End of class CountLineWordsDuplicateWords

package somePackage;
public static void main(String[] args) {
String path = ""; //ADD YOUR PATH HERE
String fileName = "test2.txt";
String testWord = "Macbeth"; //CHANGE THIS IF YOU WANT
int tLen = testWord.length();
int wordCntr = 0;
String file = path + fileName;
boolean check;
try{
FileInputStream fstream = new FileInputStream(file);
BufferedReader br = new BufferedReader(new InputStreamReader(fstream));
String strLine;
//Read File Line By Line
while((strLine = br.readLine()) != null){
//check to see whether testWord occurs at least once in the line of text
check = strLine.toLowerCase().contains(testWord.toLowerCase());
if(check){
//get the line, and parse its words into a String array
String[] lineWords = strLine.split("\\s+");
for(String w : lineWords){
//first see if the word is as least as long as the testWord
if(w.length() >= tLen){
/*
1) grab the specific word, minus whitespace
2) check to see whether the first part of it having same length
as testWord is equivalent to testWord, ignoring case
*/
String word = w.substring(0,tLen).trim();
if(word.equalsIgnoreCase(testWord)){
wordCntr++;
}
}
}
}
}
System.out.println("total is: " + wordCntr);
//Close the input stream
br.close();
} catch(Exception e){
e.printStackTrace();
}
}

public class Wordcount
{
public static void main(String[] args)
{
int count=0;
String str="hi this is is is line";
String []s1=str.split(" ");
for(int i=0;i<=s1.length-1;i++)
{
if(s1[i].equals("is"))
{
count++;
}
}
System.out.println(count);
}
}

You can read text file line by line. I assume that each line can contain more than one word. For each line, you call:
String[] words = line.split(" ");
for(int i=0; i<words.length; i++){
if(words[i].equalsIgnoreCase(searhedWord))
count++;
}

try using java.util.Scanner.
public int countWords(String w, String fileName) {
int count = 0;
Scanner scanner = new Scanner(inputFile);
scanner.useDelimiter("[^a-zA-Z]"); // non alphabets act as delimeters
String word = scanner.next();
if (word.equalsIgnoreCase(w))
count++;
return count;
}

Try it this way with Pattern and Matcher.
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Dem {
public static void main(String[] args){
try {
File f = new File("d://My.txt");
FileReader fr = new FileReader(f);
BufferedReader br = new BufferedReader(fr);
String s = new String();
while((s=br.readLine())!=null){
s = s + s;
}
int count = 0;
Pattern pat = Pattern.compile("it*");
Matcher mat = pat.matcher(s);
while(mat.find()){
if(mat.find()){
mat.start();
count++;
}
}
System.out.println(count);
} catch (Exception e) {
e.printStackTrace();
}
}
}

import java.io.*;
import java.util.*;
class filedemo
{
public static void main(String ar[])throws Exception
BufferedReader br=new BufferedReader(new FileReader("c:/file.txt"));
System.out.println("enter the string which you search");
Scanner ob=new Scanner(System.in);
String str=ob.next();
String str1="",str2="";
int count=0;
while((str1=br.readLine())!=null)
{
str2 +=str1;
}
int index = str2.indexOf(str);
while (index != -1) {
count++;
str2 = str2.substring(index + 1);
index = str2.indexOf(str);
}
System.out.println("Number of the occures="+count);
}
}

package com.test;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.Scanner;
public class Test {
public static void main(String[] args) throws Exception{
BufferedReader bf= new BufferedReader(new FileReader("src/test.txt"));
Scanner sc = new Scanner(System.in);
String W=sc.next();
//String regex ="[\\w"+W+"]";
int count=0;
//Pattern p = Pattern.compile();
String line=bf.readLine();
String s[];
do
{
s=line.split(" ");
for(String a:s)
{
if(a.contains(W))
count++;
}
line=bf.readLine();
}while(line!=null);
System.out.println(count);
}
}

public int occurrencesOfHi()
{
String newText = Text.replace("Hi","");
return (Text.length() - newText.length())/2;
}