Reading Data From A File And Putting That Data In Arrays
Feb 8, 2015
I am creating a program where it reads the data inside a file and then places this data into arrays. The file I created has numbers 1-30 in it, file named, testing1.txt .
Java Code:
public static void main(String[] args) {
// TODO Auto-generated method stub
// Variables Declaration Section
//******************************
BufferedReader br;
String sCurrentLine;
String str;
[Code] ....
My issue is that the 'str' value is not initialized, but if I initialize it, it ruins the code. I'm not sure what to do in the situation.
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Feb 8, 2015
I am creating a program where it reads the data inside a file and then places this data into arrays. The file I created has numbers 1-30 in it, file named, testing1.txt .
I am unable to post my code, it redirects me to a 'Page not found' page.
The problem with my program is a variable that I have initialized, is being said its not being initialized.
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Apr 27, 2014
I am having some trouble with a Java program. I have a txt data file, which I will display, that I need to add into two separate arrays. The text file is 8 lines long that is supposed to go into two separate 4x4 matrices. A little background info on this program, reads in two arrays, compares them and outputs the largest elements of the same index and outputs them in a separate array. I somehow cannot seem to figure out how to do this. My code is below:
Data File:
2 7 6 4
6 1 2 4
9 7 2 6
8 3 2 1
4 1 3 7
6 2 3 8
7 2 2 4
4 2 3 1
Code:
public class prog465a {
public static void main(String[] args) {
Scanner inFile = null;
try {
inFile = new Scanner(new File("prog465a.dat.txt"));
[Code] .....
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Jun 5, 2014
I can read the data to a monitor perfectly. But, I'm having problem reading data from an external file into an array of class objects. Here's my attempt at writing the method:
private void openFile()
//This method asks the user to enter a file name(including the file extension) and then
//Sets the data to an array of Product type {
String fileName, storeName="", emptyLine1="", emptyLine2="", name="", productName="";
int demandRate=0;
double setupCost=0.0, unitCost=0.0, inventoryCost=0, sellingPrice=0;
Scanner inputStream = null;
[code]...
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Feb 20, 2015
I am working on a project where as an input I need to read to data from PDF.
The PDF data will look like
As shown below:
Serial NoName of bookQuanity of BooksLibrary NamePrice
1aaa1London
2bb2Newyork
3cc1Paris
Total number of books4
Payment info
The number of books are dynamic in every pdf which I am going to receive.
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Oct 12, 2014
I have to read data from a text file and print it in a new text file. An example of one line is like this:
Johnson 85 98 75 89 82
I then have to take the average of all the numbers and assign a "grade" to the numbers for each line of the text file and make a new file so it looks like this for 10 lines:
Name 1 2 3 4 5 Average Grade
Johnson 85 98 75 89 82 85.80 B
My problem is extracting the data from the file so I can use it.
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Nov 16, 2014
I'm a complete beginner in Java programming and I'm interested to learn more about its concepts.
Recently, I've been given an exercise which instructs me to display two versions of a picture. The picture to be displayed is provided in the form of a data file of 40,000 digits that are arranged in rows (although there is no marker between rows) and it starts from the top of the picture. So the first digit represents the top left corner of the picture and the last is the bottom right.
Basically, what the exercise wants me to construct a program that plots a dot in one of two colours for each digit. If the digit is in the range 0 to 3 the output should be one colour and for digits in the range 4 to 9 the dot should be in the other colour.
I understand I have to use arrays and also loops to perform this. I'm familiar with the fillEllipse, drawEllipse, drawRectangle and fillRectangle but this exercise is nothing I've attempted before.
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Feb 8, 2014
We have an autosys job running in our production on daily basis. It calls a shell script which in turn calls a java servlet. This servlet reads these files and inserts the data into two different tables and then does some processing. Java version is 1.6 & application server is WAS7 and database is oracel-11g.
We get several issues with this process like it takes time, goes out of memory etc etc. Below are the details of the way we have coded this process.
1. When we read the file using BufferedReader, do we really get a lot of strings created in the memory as returned by readLine() method of BufferedReader? These files contain 4-5Lacs of line. All the records are separated by newline character. Is there a better way to read files in java to achieve efficiency? I couldnt find any provided the fact that all the record lines in the file are of variable length.
2. When we insert the data then we are doing a batch process with statement/prepared statement. We are making one batch containing all the records of the file. Does it really matter to break the batch size to have better performance?
3. If the tables has no indexes defined nor any other constraints and all the columns are VARCHAR type, then which operation will be faster:- inserting a new row or updating an existing row based upon some matching condition?
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Oct 11, 2014
I'm having a bit of trouble with using the Scanner and the Printwriter. I start with a file like this (1 = amount of Houses in the file)
1
FOR SALE:
Emmalaan 23
3051JC Rotterdam
7 rooms
buyprice 300000
energylevel C
The user gets (let's say for simplicity) 3 options:
1. Add a House to the file,
2. Get all Houses which fullfil requirements (price, FOR SALE / SOLD etc.) and
3. Close the application.
This is how I start:
Scanner sc = new Scanner (System.in);
while (!endLoop) {
System.out.println("Make a choice);
System.out.println("1) Add House");
System.out.println("2) Show Houses");
System.out.println("3) Exit");
int choice = sc.nextInt();
Then I have a switch for all of the three cases. I keep the scanner open, so Java can get the user input (house = for sale or sold, price = ... etc). If the user chose option 1, and all information needed is inputted and scanned, the House will be written to the file (which looks like what I typed above).
For this, I use try (PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("Makelaar.txt", false)))). This works perfectly (at least so it seems.)
If the user chose option 1, and all requirements are inputted and scanned, the Houses will be read (scanner) from the file and outputted. For this I use the same Scanner sc. This also works perfectly (so it seems atleast).
My problem is as follows: If a House has been added, I can only read the House(s) which were already in the file. Let's say I have added 2 houses, and there were from the start 3 houses. If option 2 is chosen, the first 3 houses will be scanned perfectly. An exception will be caught for the remaining 2 (just added) Houses. How can I solve this? I tried to close the Scanner, and reopening it, but apparently Java doesn't agree with this
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Dec 9, 2014
I am catching an error in my driver class that reads from a file and sorts the data based on a person's GPA. Here is my code:
import java.io.*;
import java.util.*;
public class Driver {
public static void main(String[] args) {
new Driver(args[0]);
[Code] ....
Why throwing this exception?
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Apr 5, 2014
I have an assignment on sorting, i kno i can get the sorting down but im having an issue with inputing the 512 ints in a file into an array. the instructor provided us with a file with 4 equal sets of ints. i tried to make my array of size [scan.nextInt()] and it cuts off the last 21 ints. and skips the first int. how can i get all of the integers in the text file into my array? this is what i have so far. if i hard code the array to size 50000 and then try to print the array it compiles but errors out when running it.
System.out.println("Please Enter text file in this format, XXXXX.txt :");
String file =fileName.nextLine();
Scanner scan = new Scanner(new File(file));
int [] data = new int[scan.nextInt()]; <-------here it skips first int
int count= data.length;
for (int i=0; i<data.length-1;i++) {
data[i]=scan.nextInt();
}
System.out.print(Arrays.toString(data));
rst 4 ints in output are: 501, 257, 390, 478...., supposed to be 492,501,390....and last ints are: ....88, 83, 79, 0 and supposed to be :88 83 79 77 76 72 71 71 66 57 56 48 48 41 33 30 23 23 18 17 15 13 9....it replace last ints with 0. why ? and how do i fix this. attached it the text file
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Apr 9, 2015
I would like to understand how does multipart/form-data works during file upload scenario's, Does it chunks the data from client to server while transferring the files ?
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Mar 21, 2015
By using FileReader, FileWriter and their constituents, I am creating a file to contain employee information ( name, age, hours, etc. ). The user is to input all of the data on a single line and we were asked to implement StringTokenizer to assign that data to the file. I have never used the StringTokenizer before, but I have a rough idea how it is to function. I used pw.println to test what I have so far, now I would like to let the user build the initial file with the "first employees" of the company, and then view the file, and then go back and append new employee data to that same file. My question is, how can I take the user input as a StringTokenizer and add that to the file?
In the for loop below, I thought I would see if it would work, but it does not. The loop only executes once and does not allow me to enter data.
public class Records {
public static void main(String [] args) throws IOException {
Scanner input = new Scanner(System.in);
FileWriter fw = new FileWriter("dbs3.java");
BufferedWriter bw = new BufferedWriter(fw);
PrintWriter pw = new PrintWriter(bw);
System.out.println("NEW EMPLOYEE DATA SHEET");
System.out.print("Number of new employees: ");
int number = input.nextInt();
[Code] ....
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Jan 30, 2015
Me and my mate are struggling to get our code to split a line in a text file which are separated by (":") and store into an array. We've managed to split each individual line into an array, but cannot work out how to do it with multiple splits over one line.
try{
FileReader fr = new FileReader("C:UsersTomDocumentsNetBeansPro jectsfootballA2_Tom_Tyler2srcukackingsto nci5100football_a2 om_mcLean_tyler_wattsmo delfootball_teams_phase1a.txt");
BufferedReader br = new BufferedReader(fr);
while(br.ready()){
String nextLine = br.readLine();
String[] fTArray = nextLine.split(",");
System.out.println();
for(String str : fTArray) {
System.out.println(str);
}
}
This code works but how would we do it for multiple splits over one line, along with this array?
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Aug 6, 2014
I am working on my second javafx program and I am getting confused. The program that I am writing is a payroll calculator. A secondary window opens at the start of the program where the user first enters the number of employees and clicks submit to save the number and to close this window. Then, the user begins to enters the employee information (first name, last name, pay rate and hours worked) when the user clicks the NextEmp button, I want the data in the text fields to be entered into arrays for later use, then clear the fields for the next use. I am running into 2 issues. The first is the close event for the secondary window that pops up. I cannot figure out the syntax. The second issue that I am running into is the loop to store the data into the arrays. I believe I am getting the text field data correctly, but I cannot figure out how to stop the loop until the NextEmp button is pressed again.
import javafx.application.Application;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
import javafx.scene.input.KeyCode;
[Code] .....
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Jan 23, 2015
I am just learning arrays or rather teaching myself about them and I am not to sure how they work and why. I understand that in order to set one up you do
int[] example1;
example1 = new int[]{01, 02, 03, 04};
But I don't really understand is why if you only need 3 data integers, why put the 4th one in?
Also with outputting data, I understand .print() and .println() but I am not to sure what .printf() does and then the formatting after that.
System.out.printf("%3d%11") // and then what you want to print
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Jan 21, 2015
I have two programs that talk to each other over a TCP connection. When I write the data "STX+1234" where STX is the Ascii character STX or Ctrl B and I expect the written String length to be 6 which it is. On the other side of the socket I create the ServerSocket and use the client socket's InputStream to create a BufferedReader. When I receive the string it now has 12 characters where each original character has been replaced by NUL and the character. How do I read the string as it is originally specified without the conversion? And is the problem on the reader side or the writer side?
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Apr 15, 2014
I'm trying to read user input from the terminal and separate the input into separate arrays depending on if the user input is an integer, scanner, or a string. The terminal should keep asking the user for input until the user types "quit".
import java.util.*;
public class arrayScanner {
public static void main(String[] args) {
ArrayList<Integer> intList = new ArrayList<Integer>();
ArrayList<Double> doubleList = new ArrayList<Double>();
ArrayList<String> otherList = new ArrayList<String>();
[code].....
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Feb 4, 2015
The international Olympics Committee has asked you to write a program to process the data and determine the medal winners for the pairs figure skating. You will be given the following file: Pairs.txt
Which contains the data for each pair of skaters. The data consists of each skater's name, their country and the score from each of eight judges on the technical aspects and on the performance aspects. A typical record would be as follows:
Smith
Jones
Australia
5.0 4.9 5.1 5.2 5.0 5.1 5.2 4.8
4.3 4.7 4.8 4.9 4.6 4.8 4.9 4.5
The final score for each skater is the sum of the average of the two categories of score. Design a class to hold the above data and the final score. Read the data in from the file and calculate the final score for each pair. Sort the array of objects , and display the results on the screen in order, giving special prominence to the medal winners.
Here is my CLass:
public class Skaters {
private String name1;
private String name2;
private String country;
private double [] arrTech = new double [8];
private double [] arrArt = new double [8];
private double score;
[code]...
how do i print my 2 arrays using the file? i got the name1, name2 and counntry to print but im stuck on printing the scores that are stored in the arrays. Also, i have to print the average for each array. one is for techniques and the other one is artistic. as you can see i already wrote the code for it but im stuck in printing it.
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Oct 11, 2014
Ok so I know how to import a csv using java. What I'm curious about doing is importing a csv using file chooser, reading the data, sorting the data out by certain parameters, and then outputting a count of each parameter I chose. Say for example I have columns 1,2 and 3. Column 1 has the name, column 2 has the percentage, column 3 has an o'clock time. I want to use queries to sort through the parameters and have a count of each parameter I choose...
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Jan 20, 2015
A method in Java returns a schema. In .net, we use DataTable to get the data from the schema. How to write the following code in Java:
/* Result r = method();
r.DataSchema; */
using (DataTable tbl = new DataTable())
{
using (MemoryStream ms = new MemoryStream())
using (StreamWriter sr = new StreamWriter(ms))
[code]....
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Aug 9, 2014
i tried to run simple program od adding two number by using scanner class but there is run time error here it is code file and error.
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Jan 20, 2015
I am reading Excel data using java apache. I got format issue while reading double value such as 869.87929 (in excel) into 869.8792899999999 (in java).
I'm using following files to read excel data.
1. Schema.csv: SheetName,2-int-Double
2. File.xls:
col1 | col2
123 | 869.87929
Sample code:
if(type.equals("Double")){
String str = content[i-1];
//System.out.println(str);
BigDecimal d = new BigDecimal(str);
listObjects.add(d);
}
Note: type from schema.csv & content [] value from file.xls
If I print **str**, it shows value as 869.8792899999999.
But i need to get **str** value as 869.87929. How can I get it?
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Nov 3, 2014
I'm having a lot of problems reading data from a socket. I'm trying to read the responses of a python server. I've a
BufferedReader inputStream = new BufferedReader( new InputStreamReader(socket.getInputStream()));
And then:
char[] messageChunk=new char[32768]; //32768
List<Byte> messageBytesList = new ArrayList<Byte>();
while (inputStream.ready()) {
inputStream.read(messageChunk, 0, 32768);
for(int k=0;k<32768;k++){
messageBytesList.add((byte)messageChunk[k]);
}
}
inside a thread. Then I convert the list of bytes to a byte array using:
Byte[] messageBytes = messageBytesList.toArray(new Byte[messageBytesList.size()]);
byte[] message = ArrayUtils.toPrimitive(messageBytes);
The problem is that I often receive ArrayOutOfBound errors when I try to parse the byte array. I think that I'm reading from the socket in a wrong way..
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Jan 10, 2014
My friends and me are trying to make online Test taking system. We got a very basic doubt.
We have developed classes and relationship between classes for example : Online Test Taking system will have admin and student class. And Admin will have list of students.. etc.
But question troubled me was: if we use database to store all data for example student details then I can perform all sorts of operations writing sql query and store result in some other database then what is the need of "ArrayList<Student> field in Admin".??
Question is: We can put everything in database and manipulate using database(sql) functions to manipulate it.Then what is the need of Arraylist of anything which is just used to store object details for example student details....??
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May 4, 2015
How can I Cache the data I'm reading from a collection of text files in a directory using a TreeMap? Currently my program reads the data from several text files in a directory and the saves that information in a text file called output.txt. I would like to cache this data in order to use it later. How can I do this using the TreeMap Class? These are the keys,values: TreeMap The data I'd like to Cache is (date from the file, time of the file, current time).
import java.io.*;
public class CacheData {
public static void main(String[] args) throws IOException {
String target_dir = "C:Files";
String output = "C:Filesoutput.txt";
File dir = new File(target_dir);
File[] files = dir.listFiles();
[Code] ....
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