Read CSV File From Disk And Manipulate Data Inside
Nov 17, 2014
I need to read a csv file from the disk and manipulate the data inside. My problem is that if the csv (excel format) contains "" in any of it's values the whole string line gets saved/displayed incorrectly . For example for the line in the csv file :
1,393275,57319 57321 57323 57325 57327,5_5,200000,393277,57329 57331 57333 57335 57337,3_3,200000,400000,"gi,gi",,,,,,BASS/2.4,,1
it gets read in java as :
"1,393275,57319 57321 57323 57325 57327,5_5,200000,393277,57329 57331 57333 57335 57337,3_3,200000,400000,""gi,gi"",,,,,,BASS/2.4,,1";;;;
instead as :
1,393275,57319 57321 57323 57325 57327,5_5,200000,393277,57329 57331 57333 57335 57337,3_3,200000,400000,"gi,gi",,,,,,BASS/2.4,,1
My code is :
String csvFile = "resources/testcsxs.csv" ;
String l = "";
try {
BufferedReader cz = new BufferedReader(new FileReader(csvFile));
while ((l = cz.readLine()) != null ){
System.out.println(l);
}
What am i doing wrong , how can i read a csv file (excel saved) without getting "" added incorrectly ?
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Jul 14, 2014
New to programming. Am supposed to create a program that reads a text file (of integers) and computes a series of computations on these integers. I don't have the code for the integers in my code yet, (i know how to do those), but am struggling getting the array to simply print in the print writer. I have the user select a text file, read the file with a scanner, and then save the computations done from my code into another file. specifically, the problem is as follows: Write a program that uses a file chooser dialog to select a file containing some integers. The file contains an integer N followed by N integers. The program then uses a file chooser dialog to let the user specify the name and location of an output file to write results to.The data written to the output file will be as follows
(1) The original list of N numbers from the input file,
(2) The original list of N numbers printed in reverse order of how they appear
in the input file.
(3) The sum and average of these numbers,
(4) The minimum of all the numbers,
(5) The maximum of all the numbers.
[import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Writer;
[Code]....
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Jan 29, 2015
I want to write the image file from a database to disk by using a queue. I can write these images on disk from the result set. I am wrong in the following code? I get: "trying to write to disk: Closed Connection"
{code}
public class ExtractPicture implements Runnable{
private BlockingQueue<InputStreamMessage> queue;
public ExtractPicture(BlockingQueue<InputStreamMessage> queue){
[Code].....
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Jun 19, 2014
Whenever I try to write a file to the disk and then load it within the same Class (if it is even possible) ...
It gives me an error: Could not find the main class: score.Score. Program will exit.
I have tried this with 2 different classes and it works fine? Why that error is appearing.
Code:
package score;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.Scanner;
public class Score {
public static void main(String [] args) throws Exception
[Code] .....
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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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Nov 15, 2014
I am supposed to read in a file and extract the data. I am trying to add a Long into an Array that I initialized. So this is how my method looks like :
Java Code:
public void readOSMWay(File osm){
try {
Scanner output = new Scanner(osm);
while(output.hasNext()){
String line = output.nextLine().replace("^s+","");
if(line.startsWith(" <way")){
Road way = new Road(line,true);
[Code]...
I am having problem with the else if block. I am supposed to add all the Long values into the array.
error: Java Code: The method add(Long) in the type ArrayList<Long> is not applicable for the arguments (String) mh_sh_highlight_all('java');
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Sep 10, 2014
"Write a program (save the program as ProductInventory.java) that will read data about 5 products from a text file (Products.txt. The program should use the data read from the file to create instances (objects) of Product.java(Use Product class as a Reference Type)."
I'm yet to discover how I will get the info from the textfile using scanners but I don't know how to "create instances of a reference type".
This is the code of Product.java that came with the exercise.
public class Product {
private String productCode = "";
private String productName = "";
private int quantity;
private String supplierName = "";
private String supplierAddress = "";
private double price;
[Code] .....
By the way, the exercise also required me to use the abstract class ProductLister. To be clearer, the text file is kinda like this:
54643
Rizer Mouse
Mark5s Merchandising
Marquee Mall
4
205.50
23412
Acer Ultrabook
JohnJade Merchandise
Cornal City
2
62200.00
93112
Dell Ultrabook
Octagon Marketing
Cornal City
3
68900.00
22126
Macbook Air Pro
Computerware Services
San Beda, Chad
2
93500.00
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Aug 27, 2014
I am developing a java code using netbeans for encryption decryption by RSA algorithm. Swings and file handling play a major role in these code. My encryption code is working nicely but the code for decryption is not since keys file is not being read. That is why variable mod and pri are getting null values and the following error stack is coming. I know where the problem is somewhere in void readkeys() function but cannot solve it.
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at java.math.BigInteger.modPow(BigInteger.java:1579)
at rsakeydecryption1.RsaKeyDecryption.decryption(RsaKeyDecryption1.java:167)
at rsakeydecryption1.RsaKeyDecryption.read_output(RsaKeyDecryption1.java:294)
at rsakeydecryption1.RsaKeyDecryption.actionPerformed(RsaKeyDecryption1.java:330)
[Code] .....
My code for decryption is
package rsakeydecryption1;
import java.math.BigInteger;
import java.util.Random;
import java.io.*;
import javax.swing.*;
[Code] ....
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Jun 13, 2014
I have 3 csv files as follows -
author file columns - emailID | firstname | lastname
books file columns - title | isbn | author_email | description
magazine file Columns - title | isbn | author_email | releasedate
I need to display -
1) Based on the ISBN display all books and magazines
2) All books and magazines by an author
3) All books and magazines by title
I am using Buffered reader as of now -
String csvFileToRead = "csvFiles/authors.csv";
BufferedReader br = null;
String line = "";
String splitBy = ";";
[Code] ....
I am confused about how to proceed with multiple files. Here are the approaches that i have considered -
1) change string csv csvFileToRead to a string array -
String[] csvFileToRead = {"data/autoren.csv", "data/buecher.csv", "data/zeitschriften.csv"};
Pass each index each time to a method returning all rows but getting stuck with DS to use. I think ArrayList wont suffice since i need separated data. Should i use a 2D array? Do i need to read and store data in a DS in order to achieve the goal?
2) Should i make 3 different classes with getters and setters for authors, book and magazine?
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Jul 10, 2014
I have a random access file stream. I have below code I want to written data that is currently pointed by pointer till the end and display that data on System.out Stream but it is not working my code is
//Create a Random Access File
java.io.RandomAccessFile random=new java.io.RandomAccessFile("D:/input.txt","rw");
//Position the pointer to a seek
try {
random.seek(300);
long pointer=random.getFilePointer();
System.out.println("Current Pointer is:"+pointer);
int a;
while((a=random.read())!=-1) {
System.out.println(a);
}
Where am I wrong? Although it is returning actual position of pointer in pointer using
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Nov 15, 2014
I'm trying to figure out the necessary code for reading integers from a text file, then placing them withing the two-dimensional array I have created, and then finally printing the array using a nested for-loop. I have attached the file I would like to read from. I'm having trouble figuring out how to reference the text file with the integers, and also how to properly create a dynamic preface for each row of the array. I want the preface to display as "Week #: ", with # being the row number. I tried to create an integer to be used that way, but NetBeans tells me whatever integer I declare has already been defined in method main. I know I need to use scanner to read the file. I would like the output to display like this:
Quote
Temperature Data
Week 1: 73 71 68 69 75 77 78
Week 2: 76 73 72 72 75 79 76
Week 3: 79 82 84 84 81 78 78
Week 4: 75 72 68 69 65 63 65
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Feb 24, 2015
I have a string of variable tags (tag) filled with variables, and using a Scanner (scan) to manipulate and generate data dictionary add cards for each. The variables are delimited with new line character, and the variables are structured such that the actual name of the variable contains info as to its data type, size, etc. What I need to do is move the scanner to a particular point into the string then use .nextInt() or similar. I don't want to do this to the whole variable, just where I start it from. How can I do this?
E.g..
/* variables in String tag...
ANS_s20Tx12VDstr
ANS_:Tx67MSvis
ANS_zRx11MSctr
...
..
*/
Scanner scan = new Scanner( tag );
int ptr = tag.indexOf( "_" );
ptr++;
if ( Character.toLowerCase( tag.charAt( ptr ) ) == 's' )
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Oct 19, 2014
If I want to load data in excel file into table. what is the best way to do it?
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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");
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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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Apr 14, 2015
I am learning about arrays in my class and my professor has a habit of throwing in code without explaining. We are doing a program called storing largest numbers where we read data from a file and place the larger of the two numbers in the corresponding position of a third array. They are in 4 by 4 format. Here is the ending code
import java.io.*;
import java.util.*;
public class prog464aStoringLargestNums
{
public static void main(String[] args)
[code]....
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Dec 2, 2014
I am now stuck. I am writing a program that reads information from a data file and runs it through but program. However, I am almost finished with the program, but cannot figure out the last few parts.
public class Storm {
private final double KnotsToMPH = 1.15;
// global user-defined types:
private int beginDate;
private int duration;
private String name;
[Code] .....
I have not attached the data file because it contains a total of 360 lines of hurricane information.
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Aug 7, 2014
i am fairly new to java but have made a few projects so i do know most aspects that would allow me to complete the task its just i have been stuck at the same place now for 2 days.The project is to create a java program that can read specific data within a csv file to work out the averages etc. The csv file is a database of different weather stats . an example of the first 12 months of the csv file is below..
[CSV FILE]
year ,month,average rainfall etc
1946 15.70.616108.131.5
1946 28.23.56111.871
1946 38.82932.9 102.9
1946 414.16.3029.2 150.5
1946 513.96060.7 143.6
[code]...
I know that once the data is indexed i can than use a double to find the average of the 12 specific pieces of data and so on. once this is complete i should than be able to transfer the data to a simple graph.
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Reads file: Beginningbalance.txt
Displays Data with calculation
Creates a file called "Newbalance.txt" with the following values:
111
251.41
222
402.00
With the way the code is written I can get it to create the file but it only displays one of the customers (111). I know that I need to create a loop but I am not sure how to build that. I tried creating another while loop and changing it to outFile but that was without success.
import java.io.*;
import java.util.Scanner;
import java.text.DecimalFormat;
public class Output {
public static void main(String[]args) throws IOException {
[Code] .....
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Dec 19, 2014
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/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package UI;
import java.awt.CardLayout;
import java.sql.SQLException;
import java.util.logging.Level;
[Code] ....
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Feb 26, 2015
try {
File configFile= new File("C: Documents and SettingsstudentMy DocumentsNetBeansProjectsCDASsrcconfig.xml ");
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DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(fXmlFile);
doc.getDocumentElement().normalize();
NodeList nList = doc.getElementsByTagName("config");
[Code] .....
This code is working properly but i have use path like this
File configFile= new File("srcconfig.xml");
Instead of system directory path i have to use path inside of project but i am getting an error-cannot find the specified file...
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I have this method:
Java Code:
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for (File f : list) {
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[code]....
How would I get the overall progress of reading the directory I give to it, for example, if I give it the root directory of my computer, it would read through ALL my files and folders, and that works fine.But how would I get progress for a progress bar?
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Feb 18, 2014
I'm trying to right a GUI in swing, and as part of my program, I want to open a secondary window out of the main window when a mouse clicks on the main window. Then, once I click a button on the secondary window, I want that window to close and submit data to the main window (like an info form). I have almost figured out how to do this, except for one problem. By putting a variable inside my form window called "ready," and then in my main window running a loop that constantly checks if ready is true and doesn't proceed until its true, I can create the form window, modify the values in it (currently just one value called "difficulty" that's modified by a jSlider), and then when i click the "begin" button, ready is changed to true, the form window closes, and the main window can proceed. However, when I try to put the while loop checking the ready variable inside a mouseClicked method in the main window, the form window freezes when it opens, and you can't see any of its content or modify it in any way (you can't even close it).
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//form window class
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
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[Code]...
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I have the following code which reads in data from a bluetooth transmitter, however the program is crashing upon read-in. The bluetooth connects to the device just fine, as indicated by the indicator LED on the transmitter. However during the read-in:
void beginListenForData()
is where the exception happens. Specifically, it is at the line
readBuffer[readBufferPosition++] = b;
However I don't know why it is crashing. My transmitter is sending 1 byte (0x02) at 9600 baud every 1 sec for testing purposes.
package com.example.bluetoothtest2;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
[Code] ....
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I need getting detailed examples about how I can read/insert into database using JSF code for its different components. I am a beginner in JSF and I have the basics, however, I need the best source which it has useful, easy and detailed steps to understand the techniques for connecting to the DB and how to insert or read data from the database.
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