Develop Reference

I am trying to read the first line in my .txt document in to my program?

I have this written so far, I am just doing a few practice codes from my text book. I cant seem to get this to read the first line in my .txt .
/**
*
*/
import java.util.Scanner; //needed for scanner class
import java.io.*; //needed for File I/O classes
/**
* #author Megan
*
*/
public class Pres {
/**
* #param args
*/
public static void main(String[] args) throws IOException
{
// TODO Auto-generated method stub
Scanner keyboard = new Scanner(System.in);
System.out.print("Enter name of file: C:/User/Frances/Documents/USPres.txt");
String filename = keyboard.nextLine();
File file = new File("C:/User/Frances/Documents/USPres.txt");
Scanner inputFile = new Scanner(file);
String line = inputFile.nextLine();
System.out.println("The first line in the file is: ");
System.out.println(line);
inputFile.close();
}
}
I believe it has to do with this portion of the code:
String line = inputFile.nextLine();
I am not quite sure what to type into the (), if I should type anything at all. I could be wrong. My textbook isn't to clear about the proper format. If you could help, please and thank you. :)

To read txt file do this:
String line = "";
BufferedReader in = null;
try {
in = new BufferedReader(new FileReader(fileName));
while ((line = in.readLine()) != null) {
// do something here
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
It will read all lines in the text but since it's practice go ahead and try to figure out how to read just one line.

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
public class Pres {
public static void main(String[] args) throws FileNotFoundException, IOException {
// BufferedReader is best for read line from file or else
BufferedReader Bfr = new BufferedReader(new FileReader("your_filename_or_path.txt"));
// get first line from file
String firstLinetext = Bfr .readLine();
System.out.println(firstLinetext ); // print first line
}
}

using Java arraylist for storing data from scan from file

I am new to java, but not coding. I am trying to figure out java because it's part of my class this term and I am having a really hard problem grasping the idea of it and implementing things in java.
my problem Is that I am not sure if I am correctly using the arraylist to grab data from the scan of the file and input it into a arraylist to sort and print at a later time. I am just having issues picking up on java any help would be great since I am new to java.
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.regex.Pattern;
import java.util.ArrayList;
import java.util.*;
public class MissionCount
{
private static ArrayList<String> list = new ArrayList<String>();
// returns an InputStream that gets data from the named file
private static InputStream getFileInputStream(String fileName) throws Exception {
InputStream inputStream;
try {
inputStream = new FileInputStream(new File(fileName));
}
catch (FileNotFoundException e) { // no file with this name exists
inputStream = null;
throw new Exception("unable to open the file -- " + e.getMessage());
}
return inputStream;
}
public static void main(String[] args) {
if (args.length != 1) {
System.out.println("USage: MissionCount <datafile>");
//System.exit(1);
}
try {
System.out.printf("CS261 - MissionCount - Chad Dreher%n%n");
int crewcount = 0;
int misscount = 0;
InputStream log = getFileInputStream(args[0]);
Scanner sc = new Scanner(log);
sc.useDelimiter(Pattern.compile(",|\n"));
while (sc.hasNext()) {
String crewMember = sc.next();
list.add(crewMember);
String mission = sc.next();
list.add(mission);
}
sc.close();
// Add code to print the report here
}catch (Exception e) {
System.out.println("Error: " + e.getMessage());
}
}
}

InputStream log = getFileInputStream(args[0]);
Change that line to as follows :-
File log = new File(args[0])
that should work!

cannot create a txt file

import java.util.Scanner;
import java.io.FileInputStream;
import java.io.PrintWriter;
import java.io.FileOutputStream;
import java.io.FileNotFoundException;
public class Exercise4
{
String name = null;
public String nameInitials(String sentence)
{
PrintWriter outputStream = null;
try
{
outputStream = new PrintWriter(new FileOutputStream("abc.txt."));
outputStream.println(sentence);
}
catch (FileNotFoundException e)
{
System.out.println("File not found.");
System.exit(0);
}
outputStream.close();
Scanner inputStream = null;
try
{
inputStream = new Scanner(new FileInputStream("abc.txt."));
}
catch (FileNotFoundException e)
{
System.out.println("File not found.");
System.exit(0);
}
do
{
String word = inputStream.next();
char initial = word.charAt(0);
name = initial+"."+name;
} while (inputStream.hasNext());
return name;
}
public void main(String[]args)
{
String initials = nameInitials("Bertrand Arthur William Russell");
System.out.println(initials);
}
}
Write a method called nameInitials that takes one String as argument, pertaining to somebody's full name and returns a String of the name's initials. Usage example,
String initials = nameInitials("Bertrand Arthur William Russell");
System.out.println(initials); //should print B.A.W.R.
I try to store the full name to a txt file and read the file. But I don't know why I cannot create the abc.txt file in the folder.

This can fix your error, I tested it
import java.util.Scanner;
import java.io.FileInputStream;
import java.io.PrintWriter;
import java.io.FileOutputStream;
import java.io.FileNotFoundException;
public class Exercise4
{
static String name = null;
public static String nameInitials(String sentence) {
PrintWriter outputStream = null;
try {
outputStream = new PrintWriter(new FileOutputStream("C:\\temp\\abc.txt"));
outputStream.println(sentence);
} catch (FileNotFoundException e) {
System.out.println("File not found.");
System.exit(0);
}
outputStream.close();
Scanner inputStream = null;
try {
inputStream = new Scanner(new FileInputStream("C:\\temp\\abc.txt"));
} catch (FileNotFoundException e) {
System.out.println("File not found.");
System.exit(0);
}
do {
String word = inputStream.next();
char initial = word.charAt(0);
name = initial + "." + name;
} while (inputStream.hasNext());
return name;
}
public static void main(String[] args) {
String initials = nameInitials("Bertrand Arthur William Russell");
System.out.println(initials);
}
}
the path of file not should end of .txt. just .txt

Your code is perfect it is creating the file "abc.txt." at the project level If you want to create a file named abc.txt then you must change;
new FileOutputStream("abc.txt.") to new FileOutputStream("abc.txt")
and
new FileInputStream("abc.txt.") to new FileInputStream("abc.txt")
And if you want to create the file in a particular directory then provide the full path of that directory with the file name you want to create.
for ubuntu system;
new FileOutputStream("/home/java/abc.txt")
&
new FileInputStream("/home/java/abc.txt")
and for windows system;
new FileOutputStream("C:/java/abc.txt")
&
new FileInputStream("C:/java/abc.txt")

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) {
}
}
}
}