Develop Reference

listing the frequency of words from multiple files

I've created a program that will look at a text file in a certain directory and then proceed to list the words in that file.
So for example if my text file contained this.
hello my name is john hello my
The output would show
hello 2
my 2
name 1
is 1
john 1
However now I want my program to search through multiple text files in directory and list all the words that occur in all the text files.
Here is my program that will list the words in a single file.
import java.io.File;
import java.io.FileNotFoundException;
import java.util.HashMap;
import java.util.Scanner;
public class WordCountstackquestion implements Runnable {
private String filename;
public WordCountstackquestion(String filename) {
this.filename = filename;
}
public void run() {
int count = 0;
try {
HashMap<String, Integer> map = new HashMap<String, Integer>();
Scanner in = new Scanner(new File(filename));
while (in.hasNext()) {
String word = in.next();
if (map.containsKey(word))
map.put(word, map.get(word) + 1);
else {
map.put(word, 1);
}
count++;
}
System.out.println(filename + " : " + count);
for (String word : map.keySet()) {
System.out.println(word + " " + map.get(word));
}
} catch (FileNotFoundException e) {
System.out.println(filename + " was not found.");
}
}
}
My main class.
public class Mainstackquestion
{
public static void main(String args[])
{
if(args.length > 0)
{
for (String filename : args)
{
CheckFile(filename);
}
}
else
{
CheckFile("C:\\Users\\User\\Desktop\\files\\1.txt");
}
}
private static void CheckFile(String file)
{
Runnable tester = new WordCountstackquestion(file);
Thread t = new Thread(tester);
t.start();
}
}
I've made an attempt using some online sources to make a method that will look at multiple files. However I'm struggling and can't seem to implement it correctly in my program.
I would have a worker class for each file.
int count;
#Override
public void run()
{
count = 0;
/* Count the words... */
...
++count;
...
}
Then this method to use them.
public static void main(String args[]) throws InterruptedException
{
WordCount[] counters = new WordCount[args.length];
for (int idx = 0; idx < args.length; ++idx) {
counters[idx] = new WordCount(args[idx]);
counters[idx].start();
}
int total = 0;
for (WordCount counter : counters) {
counter.join();
total += counter.count;
}
System.out.println("Total: " + total);
}

I'm going to assume that all of these files lie in the same directory. You can do it this way:
public void run() {
// Replace the link to your filename variable
File f = new File("link/to/folder/here");
// Check if file is a directory (always do this if you are going to use listFiles()
if (f.isDirectory()) {
// I've moved to scanner object outside the code in order to prevent mass creation of an object
Scanner in = null;
// Lists all files in a directory
// You could also use a for loop, but I prefer enchanced for loops
for (File file : f.listFiles()) {
// Everything here is your old code, utilizing a new file (now named "f" instead of "filename"
int count = 0;
try {
HashMap<String, Integer> map = new HashMap<String, Integer>();
in = new Scanner(f);
while (in.hasNext()) {
String word = in.next();
if (map.containsKey(word))
map.put(word, map.get(word) + 1);
else {
map.put(word, 1);
}
count++;
}
System.out.println(f + " : " + count);
for (String word : map.keySet()) {
System.out.println(word + " " + map.get(word));
}
} catch (FileNotFoundException e) {
System.out.println(file + " was not found.");
}
}
// Once done with the scanner, close it (I didn't see it in your code, so including it now)
in.close();
}
}
If you wanted to use a for loop rather than an enhanced for loop (for compatibility purposes), the link shared in the comments.
Otherwise, you can just keep scanning user input, and throwing it all into an ArrayList (or some other form of an ArrayList, whatever is required for your needs) and loop through the arraylist and move around the "File f" variable (to inside the loop), sorta like this:
for(String s : arraylist){
File f = new File(s);
}

How do i load a text file into this program?

How do i go about loading a text file into a java program that i have posted below. I have tried but am out of luck, any help will be appreciated!
Thank you.
import java.io.*;
public class test1 {
public static void main(String args[]) throws Exception {
if (args.length != 1) {
System.out.println("usage: Tut16_ReadText filename");
System.exit(0);
}
try {
FileReader infile = new FileReader(args[0]);
BufferedReader inbuf = new BufferedReader(infile);
String str;
int totalwords = 0, totalchar = 0;
while ((str = inbuf.readLine()) != null) {
String words[] = str.split(" ");
totalwords += words.length;
for (int j = 0; j < words.length; j++) {
totalchar += words[j].length();
}
}
double density = (1.0 * totalchar) / totalwords;
if (totalchar > 0) {
System.out.print(args[0] + " : " + density + " : ");
if (density > 6.0)
System.out.println("heavy");
else
System.out.println("light");
} else
System.out.println("This is an error - denisty of zero.");
infile.close();
} catch (Exception ee) {
System.out.println("This is an error - execution caught.");
}
}
}

If you are running java 8 it is a breeze with the new io streams. Advantage is on large file all text is not read into memory.
public void ReadFile(String filePath){
File txtFile = new File(filePath);
if (txtFile.exists()) {
System.out.println("reading file");
try (Stream<String> filtered = Files.
lines(txtFile.toPath()).
filter(s -> s.contains("2006]"))) {//you can leave this out, but is handy to do some pre filtering
filtered.forEach(s -> handleLine(s));
}
} else {
System.out.println("file not found");
}
}
private void handleLine(String lineText) {
System.out.println(lineText);
}

First of all, there is an easier way to read files. From Java 7 the Files and Paths classes can be used like this:
public static void main(String[] args) throws IOException {
if (args.length != 1) {
System.out.println("usage: Tut16_ReadText filename");
System.exit(0);
}
final List<String> lines = Files.readAllLines(Paths.get(args[0]));
for (String line : lines) {
// Do stuff...
}
// More stuff
}
Then, in order to start the program and get it to read a file that you specify you must provide an argument when starting the app. You pass that argument after the class name on the command prompt like this:
$ java Tut16_ReadText /some/path/someFile.txt
This passes "/some/path/someFile.txt" to the program and then the program will try to read that file.

Another method is to use a Scanner.
Scanner s = new Scanner(new File(args[0]));
while(s.hasNext()){..}

calling method with IOException

I had this program with which i have to check if the value the user entered is present in the text file i created in the source file. However it throws me an error everytime i try to call the method with IOException. Please help me out thanks.
import java.util.*;
import java.io.*;
public class chargeAccountModi
{
public boolean sequentialSearch ( double chargeNumber ) throws IOException
{
Scanner keyboard= new Scanner(System.in);
int index = 0;
int element = -1;
boolean found = false;
System.out.println(" Enter the Charge Account Number : " );
chargeNumber = keyboard.nextInt();
int[] tests = new int[18];
int i = 0;
File file = new File ("Names.txt");
Scanner inputFile = new Scanner(file);
while(inputFile.hasNext() && i < tests.length )
{
tests [i] = inputFile.nextInt();
i++;
}
inputFile.close();
for ( index = 0 ; index < tests.length ; index ++ )
{
if ( tests[index] == chargeNumber )
{
found = true;
element = index;
}
}
return found;
}
public static void main(String[]Args)
{
double chargeNumber = 0;
chargeAccountModi object1 = new chargeAccountModi();
try
{
object1.sequentialSearch(chargeNumber);
}
catch (IOException ioe)
{
}
System.out.println(" The search result is : " + object1.sequentialSearch (chargeNumber));
}
}

After looking on your method sequentialSearch there is everythink ok. But try to change main:
But remember that in your Names.txt file you should have only numbers because you use scanner.nextInt();, so there should be only numbers or method will throw exeption InputMismatchException.
Check also path to Names.txt file you should have it on classpath because you use relative path in code File file = new File ("Names.txt"); Names.txt should be in the same folder.
public static void main(String[]Args)
{
double chargeNumber = 0;
chargeAccountModi object1 = new chargeAccountModi();
try
{
System.out.println(" The search result is : " + object1.sequentialSearch(chargeNumber));
}
catch (IOException ioe)
{
System.out.println("Exception!!!");
ioe.printStackTrace();
}
}

Few tips and suggestions:
First of all: Don't forget to close the Scanner objects! (you left one unclosed)
Second of all: Your main method is highly inefficient, you are using two loops, in the first one you read and store variables, in the second one you check for a match, you can do both at the same time (I've written an alternative method for you)
Third little thing: The variable "element" is not used at all in your code, I've removed it in the answer.
And last but not least: The file "Names.txt" needs to be located (since you've only specificied it's name) in the root folder of your project, since you mention an IOException, I figure that's what's wrong with the app. If your project is called Accounts, then it's a folder called Accounts with it's source and whatever else is part of your project, make sure the file "Accounts/Names.txt" exists! and that it is in the desired format.
import java.util.*;
import java.io.*;
public class ChargeAccountModi {
public boolean sequentialSearch(double chargeNumber) throws IOException {
Scanner keyboard= new Scanner(System.in);
int index = 0;
boolean found = false;
System.out.print("Enter the Charge Account Number: " );
chargeNumber = keyboard.nextInt();
int[] tests = new int[18];
int i = 0;
File file = new File ("Names.txt");
Scanner inputFile = new Scanner(file);
while(inputFile.hasNext() && i < tests.length ) {
tests [i] = inputFile.nextInt();
i++;
}
inputFile.close();
for (index = 0 ; index < tests.length ; index ++ ) {
if (tests[index] == chargeNumber) {
found = true;
}
}
keyboard.close();
return found;
}
public boolean sequentialSearchAlternative(double chargeNumber) throws IOException {
Scanner keyboard= new Scanner(System.in);
boolean found = false;
System.out.print("Enter the Charge Account Number: " );
chargeNumber = keyboard.nextInt();
int tests = 18;
int i = 0;
File file = new File ("Names.txt");
Scanner inputFile = new Scanner(file);
while(inputFile.hasNext() && i<tests) {
if (inputFile.nextInt() == chargeNumber) {
found = true;
break;
}
i++;
}
inputFile.close();
keyboard.close();
return found;
}
public static void main(String[] args) {
double chargeNumber = 0;
ChargeAccountModi object1 = new ChargeAccountModi();
try {
System.out.println("The search result is : " + object1.sequentialSearch(chargeNumber));
} catch (Exception e) {
//Handle the exceptions here
//The most likely exceptions are:
//java.io.FileNotFoundException: Names.txt - Cannot find the file
//java.util.InputMismatchException - If you type something other than a number
e.printStackTrace();
}
}
}

Scanner will take user input but will not find the file

This is a program to read a file and print out the file with some of the text edited. The code will compile the issue is that it will read the users input but will say file is not found when the file is there. I feel like I am missing something. I am brand new at this so go easy on me.

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class MainTest {
public static void main(String args[]) {
// if (args[0] != null)
readFile();
}
public static void readFile() { // Method to read file
Scanner inFile = null;
String out = "";
try {
Scanner input = new Scanner(System.in);
System.out.println("enter file name");
String filename = input.next();
File in = new File(filename); // ask for the file name
inFile = new Scanner(in);
int count = 0;
while (inFile.hasNextLine()) { // reads each line
String line = inFile.nextLine();
for (int i = 0; i < line.length(); i++) {
char ch = line.charAt(i);
out = out + ch;
if (ch == '{') {
count = count + 1;
out = out + " " + count;
} else if (ch == '}') {
out = out + " " + count;
if (count > 0) {
count = count - 1;
}
}
}
}
System.out.println(out);
} catch (FileNotFoundException exception) {
System.out.println("File not found.");
}
inFile.close();
}
}

You can use System.getProperty("user.dir") to find where Scanner looking to find your file. And you should be sure your file is located here.

get number of files in a directory and its subdirectories

using this code
new File("/mnt/sdcard/folder").listFiles().length
returns a sum of folders and files in a particular directory without caring about subdirectories.
I want to get number of all files in a directory and its subdirectories.
P.S. : hardly matters if it returns a sum of all the files and folders.
any help appreciated,
thanks

Try this.
int count = 0;
getFile("/mnt/sdcard/folder/");
private void getFile(String dirPath) {
File f = new File(dirPath);
File[] files = f.listFiles();
if (files != null)
for (int i = 0; i < files.length; i++) {
count++;
File file = files[i];
if (file.isDirectory()) {
getFile(file.getAbsolutePath());
}
}
}
It may help you.

You can use recursion.
public static int getFilesCount(File file) {
File[] files = file.listFiles();
int count = 0;
for (File f : files)
if (f.isDirectory())
count += getFilesCount(f);
else
count++;
return count;
}

Using Java 8 NIO:
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class Test {
public long fileCount(Path dir) {
return Files.walk(dir)
.parallel()
.filter(p -> !p.toFile().isDirectory())
.count();
}
public void main(String... args) {
Path dir = Paths.get(args[0]);
long count = fileCount(dir);
System.out.println(args[0] + " has " + count + " files");
}
}

public Integer countFiles(File folder, Integer count) {
File[] files = folder.listFiles();
for (File file: files) {
if (file.isFile()) {
count++;
} else {
countFiles(file, count);
}
}
return count;
}
Usage:
Integer count = countFiles(new File("your/path"), Integer.valuOf(0));

you will have to do a recursive search over your files.
Use `File#isDrirectory()´ to check if a file is a directory and traverse the file tree down.

You have to go though all the folder recursively and find out the files
int mCount;
getTotalFiles(File dir) {
File[] files = dir.listFiles();
for (File file : files) {
if (file.isDirectory()) {
getTotalFiles(file);
} else {
mCount++;
}
}
}

Something I've used before, you can easily edit it to get what you want:
public class Filewalker {
public void walk( String path ) {
File root = new File( path );
File[] list = root.listFiles();
for ( File f : list ) {
if ( f.isDirectory() ) {
walk( f.getAbsolutePath() );
System.out.println( "Dir:" + f.getAbsoluteFile() );
}
else {
System.out.println( "File:" + f.getAbsoluteFile() );
}
}
}
public static void main(String[] args) {
Filewalker fw = new Filewalker();
fw.walk("c:\\" );
}
}

Here's a short one all encapsulated within a single method just returning the number of files and directories within a specific directory:
public static int countFiles(File directory) {
int count = 0;
for (File file : directory.listFiles()) {
if (file.isDirectory()) {
count += countFiles(file);
}
count++;
}
return count;
}
Cheers!

Just for the record, you may also use iteration instead of recursion:
public static int countFiles(final File dir) {
final ArrayDeque<File> dirs = new ArrayDeque<>();
dirs.add(dir);
int cnt = 0;
while (!dirs.isEmpty()) {
final File[] files = dirs.poll().listFiles();
for (final File f: files)
if (f.isDirectory())
dirs.add(f);
else
++cnt;
}
return cnt;
}
In this implementation I'm using ArrayDeque but you can use any Queue or any List for the job.

public int numberOfFiles(File srcDir) {
int count = 0;
File[] listFiles = srcDir.listFiles();
for(int i = 0; i < listFiles.length; i++){
if (listFiles[i].isDirectory()) {
count += numberOfFiles(listFiles[i]);
} else if (listFiles[i].isFile()) {
count++;
}
}
return count;
}

http://www.java2s.com/Code/Java/File-Input-Output/Countfilesinadirectoryincludingfilesinallsubdirectories.htm
public static int countFilesInDirectory(File directory) {
int count = 0;
for (File file : directory.listFiles()) {
if (file.isFile()) {
count++;
}
if (file.isDirectory()) {
count += countFilesInDirectory(file);
}
}
return count;
}
refer this site
it gives perfect answer

import java.io.File;
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println("Enter the Path for Directory/Folder Name");
String Directory=sc.nextLine();
System.out.println("Your Directory/folder is :"+Directory);
File f = new File(Directory);
int countFiles = 0;
int countDirectory=0;
for (File file : f.listFiles()) {
if (file.isFile()) {
countFiles++;
}
if (file.isDirectory()) {
countDirectory++;
}
}
System.out.println("Number of files in Directory : " + countFiles+"\nNumber of Sub-directories "+countDirectory);
}
}