Reading from a text file into a 2D array

How do you read from a text file and put it into a 2D array? Or if someone could guide me to where I can find the information?

This tutorial shows how to read a file:
http://java.sun.com/docs/books/tutorial/essential/io/scanfor.html
This tutorial shows how to create arrays with multiple dimensions:
http://java.sun.com/docs/books/tutorial/java/nutsandbolts/arrays.html

Similar Messages

Reading from a text file in to an array, help please

I have the following
public class date extends Loans{
public int dd;
public int mm;
public int yyyy;
public String toString() {
return String.format( "%d,%d,%d", mm, dd, yyyy );
public class Loans extends Borrowing {
public String name;
public String book;
public date issue;
public char type;
public String toString(){
return String.format( "%s, %s, %s, %s", name, book, issue, type );
import java.util.Scanner;
import java.io.*;
public class Borrowing extends BorrowingList {
private Loans[] Loaned = new Loans[20];
if i want to read in from a text file in to that array how do i do it?

sorry to keep bothering you and thanks loads for your help but now I am getting the following error mesage
C:\Documents and Settings\MrW\Menu.java:43: cannot find symbol
symbol : class IOException
location: class Menu
}catch(IOException e){
Note: C:\Documents and Settings\MrW\Borrowing.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 error
BUILD FAILED (total time: 0 seconds)
for this line
}catch(IOException e){

Reading characters from a text file into a multidimensional array?

I have an array, maze[][] that is to be filled with characters from a text file. I've got most of the program worked out (i think) but can't test it because I am reading my file incorrectly. However, I'm running into major headaches with this part of the program.
The text file looks like this: (It is meant to be a maze, 19 is the size of the maze(assumed to be square). is free space, # is block, s is start, x is finish)
This didn't paste evenly, but thats not a big deal. Just giving an idea.
19
5..................
And my constructor looks like follows, I've tried zillions of things with the input.hasNext() and hasNextLine() to no avail.
Code:
//Scanner to read file
Scanner input = null;
try{
input = new Scanner(fileName);
}catch(RuntimeException e) {
System.err.println("Couldn't find the file");
System.exit(0);
//Set the size of the maze
while(input.hasNextInt())
size = input.nextInt();
//Set Limits on coordinates
Coordinates.setLimits(size);
//Set the maze[][] array equal to this size
maze = new char[size][size];
//Fill the Array with maze values
for(int i = 0; i < maze.length; i++)
for(int x = 0; x < maze.length; x++)
if(input.hasNextLine())
String insert = input.nextLine();
maze[i][x] = insert.charAt(x);
Any advice would be loved =D

Code-tags sometimes cause wonders, I replaced # with *, as the code tags interprets # as comment, which looks odd:
******...*.........To your code: Did you test it step by step, to find out about what is read? You could either use a debugger (e.g., if you have an IDE) or system outs to get a clue. First thing to check would be, if the maze size is read correctly. Further, the following loops look odd:for(int i = 0; i < maze.length; i++) {
    for(int x = 0; x < maze.length; x++) {
        if (input.hasNextLine()) {
            String insert = input.nextLine();
            maze[x] = insert.charAt(x);
}Shouldn't the nextLine test and assignment be in the outer loop? And assignment be to each maze's inner array? Like so:for(int i = 0; i < maze.length; i++) {
    if (input.hasNextLine()) {
        String insert = input.nextLine();
        for(int x = 0; x < insert.size(); x++) {
            maze[i][x] = insert.charAt(x);
}Otherwise, only one character per line is read and storing a character actually should fail.

Read words from a text file into an undefined array

Dear all,
Does anyone know how to read words in text file, seperated by all types of spaces ("_", "\n", "\t","\r","\f") and put them into a string array to be used later?
So far I can read the words using the Tokenizer but can't assign to array:
public class reader
StringTokenizer tokenizer = new StringTokenizer(input);
String[ ] array= null; //unknown size of array
int i=0;
               while(tokenizer.hasMoreTokens())
                         array[i] = tokenizer.nextToken();
                         i++;
Any suggestions welcome!
thanks in advance!

Hi
sorry wrote in a hurry ;) din c the problem clearly
there are two approaches
1) best approach for your problem is Vector or ArrayList, these would make life easy for you.
Always collections are better approach over arrays when the size is dynamic. However in your case the size cant be said to be DYNAMIC. coz the number of words will not grow / shrink during the runtime.. i know that number of words are not fixed but dynamic is something which will grow/shrink during runtime. but still collection is better approach.
2)dirty approach
use double dimensional array
String arr[][] = null;
then use one tokenizer for StringTokenizer(str,"\n");
using countTokens on this will give you number of lines.
use this to initialize array
arr = new String[lineCount][];
then iterate from 1 to lineCount and use 1 more tokenizer to get number of words for that line. use this number to initialize the column size for arr[i] like
arr[i] = new String[wordCount];
then store the token using nested for loops in this array
go for the 1st one ;) 2nd one is hedious n time consuming but both will work ;)
cheers
amey

Reading one line from a text file into an array

i want to read one line from a text file into an array, and then the next line into a different array. both arays are type string...i have this:
public static void readAndProcessData(FileInputStream stream){
     InputStreamReader iStrReader = new InputStreamReader (stream);
     BufferedReader reader = new BufferedReader (iStrReader);
     String line = "";
     try{
     int i = 0;
          while (line != null){
               names[i] = reader.readLine();
               score[i] = reader.readLine();
               line = reader.readLine();
               i++;
          }catch (IOException e){
          System.out.println("Error in file access");
this section calls it:
try{
     FileInputStream stream = new FileInputStream("ISU.txt");
          HighScore.readAndProcessData(stream);
          stream.close();
          names = HighScore.getNames();
          scores = HighScore.getScores();
     }catch(IOException e){
          System.out.println("Error in accessing file." + e.toString());
it gives me an array index out of bounds error

oh wait I see it when I looked at the original quote.
They array you made called names or the other one is prob too small for the amount of names that you have in the file. Hence as I increases it eventually goes out of bounds of the array so you should probably resize the array if that happens.

How to read a whole text file into a pl/sql variable?

Hi, I need to read an entire text file--which actually contains an email message extracted from a content management system-- into a variable in a pl/sql package, so I can insert some information from the database and then send the email. I want to read the whole text file in one shot, not just one line at a time. Shoud I use Utl_File.Get_Raw or is there another more appropriate way to do this?

how to read a whole text file into a pl/sql variable?
your_clob_variable := dbms_xslprocessor.read2clob('YOUR_DIRECTORY','YOUR_FILE');
....

How to read from a text file one character at a time?

Hello
I wish to read from a text file in a for loop and that on every iteration i read one charachter and proceed to the next one.
can anyone help me?
Lavi

lava wrote:
I wish to read from a text file in a for loop and that on every iteration i read one charachter and proceed to the next one.
can anyone help me?
Some additional comments:
You really don't want to read any file one character at a time, because it is highly inefficient. More typically, you read the entire file into memory with one operation (or at least a large chunk, if the file is gigantic) and then do the rest of the operations in memory. One easy way to analyze it one byte at a time would be to use "string to byte array" and then autoindex into a FOR loop, for example.
Of course you could also read the file directly as a U8 array instead of a string.
Message Edited by altenbach on 06-10-2008 08:57 AM
LabVIEW Champion . Do more with less code and in less time .

HOW TO WRITE AND READ FROM A TEXT FILE???

How can I read from a text file and then display the contents in a JTextArea??????
Also how can I write the contents of a JTextArea to a text file.
Extra Question::::::: Is it possible to write records to a text file. If you have not idea what I am talking about then ignore it.
Manny thanks,
your help is much appreciated though you don't know it!

Do 3 things.
-- Look through the API at the java.io package.
-- Search previous posts for "read write from text file"
-- Search java.sun.com for information on the java.io package.
That should clear just about everything up. If you have more specific problems, feel free to come back and post them.

Getting repeated values when reading from a text file.

I need to read from a text file. When the token encounters a particular word (command) I need to read the next line and perform some actions. However, this part is working but it is repeating the values again and again until it encounters the next particular word (command). Hope that someone will help me out, as always when I posted a problem in these forums.
SetOperations class - contains the set methods
// Imported packages.========================================================
import java.util.Vector;
import java.util.Iterator;
// Public class SetOperations.===============================================
public class SetOperations
     // Instance variables.===================================================
     private Vector v = null; // Creates new instance of vector.
     protected int memberCount;
     // Constructor.==========================================================
     public SetOperations()
          v = new Vector();
     } // end constructor.
     // Method isMember.======================================================
     * Checks whether the element is already a member of the set.
     * @return True if Vector v contains Object member.
     public boolean isMember(Object member)
          if (member != null) // only if Object member is not null.
               return v.contains(member); // returns true if vector already contains member.
          else
               return false; // returns false if vector does not contain member.
     } // end public boolean isMember(Object member).
     // Method addMember.=====================================================
     * Adds a member to the set.
     * @return Adds Object member to Vector v.
     public void addMember(Object member)
          //if (! v.contains(member)) // only if element is not already a member.
          if (isMember(member) == false) // only if element is not already a member.
               v.add(member); // adds a member.
     } // end public void addMember(Object member).
     // Method countMember.===================================================
     * Returns the number of members present in the vector.
     * @return Number of elements present in the vector.
     public int countMember()
          return v.size();
     } // end public int countMember().
     // Method isSetEmpty.====================================================
     * Returns true if set is empty.
     * @return True if no elements are present in Vector v.
     public boolean isSetEmpty()
          return v.size() == 0; // returns 0 if no elements are present in the vector.
     } // end of public boolean isSetEmpty().
     // Method printMember.===================================================
     * Displays member/s of the set.
     * @return Prints element/s present in the vector.
     public void printMember()
          for (int i = 0; i < v.size(); i++) // iterates through present members.
               System.out.println("[" + i + "] " + v.get(i)); // displays member/s present in the vector.
     } // end of public void printMember().
} // end public class SetOperations.
SetTextLauncher class - reads from a text file and implements the set operations
// Imported packages.========================================================
import java.util.*;
import java.io.*;
// Public class SetTestLauncher.=============================================
public class SetTestLauncher
     // Main method public static void main(String args[]).===================
     public static void main(String args[])
          displayFile("test.txt"); // outputs result from text file.
     // method to display a file on screen
     public static void displayFile (String textFile)
          // Instance variables.===============================================
          // Creates new instances of SetOperations.
          SetOperations setA = new SetOperations();
          SetOperations setB = new SetOperations();
          SetOperations setC = new SetOperations();
          SetOperations setD = new SetOperations();
          SetOperations setE = new SetOperations();
          // Initialisation.
          String line = "", nextLine = "";
          FileReader fr = null;
          try
               // Opens the file with the FileReader data sink stream.
               fr = new FileReader(textFile);
               // Converts the FileReader input stream with the BufferedReader processing stream.
               BufferedReader br = new BufferedReader(fr);
               // Iterates through text file reading lines until end of text lines.
               while (line != null)
                    line = br.readLine(); // reads one line at a time.
                    if(line == null) break; // when the line is null break the loop.
                    // Creates a new instace of StringTokenizer.
                    StringTokenizer st = new StringTokenizer(line);
                    // Loops until there are no more tokens.
                    while (st.hasMoreTokens())
                         String token = st.nextToken(); // reads next token.
                         // Only if the token encounters the String "membera".
                         if(token.equals("membera"))
                              nextLine = br.readLine(); // gets next line.
                              setA.addMember(nextLine); // adds a member to the set.
                              // Displays members present in the set if vector is not empty.
                              if (! setA.isSetEmpty())
                                   setA.printMember(); // print members present.
                              // Displays the number of member/s present in the vector.
                              System.out.println("Number of set members: " + setA.countMember());
          // Catches and displays exceptions.
          catch (FileNotFoundException exp)
               System.out.println(exp.getMessage());
               exp.printStackTrace();
          catch (IOException exp)
               System.out.println(exp.getMessage());
               exp.printStackTrace();
          finally
               try
                    // if file is found
                    if (fr != null)
                         // close file
                         fr.close();
               catch (IOException exp)
                    exp.printStackTrace();
     } // end public static void main(String args[]).
} // end public class SetTestLauncher.

Thanks for your interest. Please ignore SetOperations class, it is just the class containing the methods and it works correctly since I checked it without reading from a text file. I marked the part where I think lies my problem in class SetTestOperations.
The information in the text file is as follows:
membera
Hillman
membera
Skoda
membera
Honda
membera
Toyota
and the result is:
[0] Hillman
Number of set members: 1
[0] Hillman
[1] Skoda
Number of set members: 2
[0] Hillman
[1] Skoda
[2] Honda
Number of set members: 3
[0] Hillman
[1] Skoda
[2] Honda
[3] Toyota
Number of set members: 4
instead of just one set:
[0] Hillman
[1] Skoda
[2] Honda
[3] Toyota
Number of set members: 4
Hope it is easier to understand like this.
Regards
Marco
I need to read from a text file. When the token
encounters a particular word (command) I need to read
the next line and perform some actions. However, this
part is working but it is repeating the values again
and again until it encounters the next particular
word (command). Hope that someone will help me out,
as always when I posted a problem in these forums.
SetOperations class - contains the set
methods
// Imported
packages.=============================================
===========
import java.util.Vector;
import java.util.Iterator;
// Public class
SetOperations.========================================
=======
public class SetOperations
// Instance
e
variables.============================================
=======
private Vector v = null; // Creates new instance of
f vector.
     protected int memberCount;
Constructor.==========================================
================
     public SetOperations()
          v = new Vector();
     } // end constructor.
// Method
d
isMember.=============================================
=========
* Checks whether the element is already a member of
f the set.
     * @return True if Vector v contains Object member.
     public boolean isMember(Object member)
if (member != null) // only if Object member is not
ot null.
return v.contains(member); // returns true if
if vector already contains member.
          else
return false; // returns false if vector does not
not contain member.
     } // end public boolean isMember(Object member).
// Method
d
addMember.============================================
=========
     * Adds a member to the set.
     * @return Adds Object member to Vector v.
     public void addMember(Object member)
//if (! v.contains(member)) // only if element is
is not already a member.
if (isMember(member) == false) // only if element
nt is not already a member.
               v.add(member); // adds a member.
     } // end public void addMember(Object member).
// Method
d
countMember.==========================================
=========
* Returns the number of members present in the
e vector.
     * @return Number of elements present in the vector.
     public int countMember()
          return v.size();
     } // end public int countMember().
// Method
d
isSetEmpty.===========================================
=========
     * Returns true if set is empty.
* @return True if no elements are present in Vector
r v.
     public boolean isSetEmpty()
return v.size() == 0; // returns 0 if no elements
ts are present in the vector.
     } // end of public boolean isSetEmpty().
// Method
d
printMember.==========================================
=========
     * Displays member/s of the set.
     * @return Prints element/s present in the vector.
     public void printMember()
for (int i = 0; i < v.size(); i++) // iterates
es through present members.
System.out.println("[" + i + "] " + v.get(i)); //
// displays member/s present in the vector.
     } // end of public void printMember().
} // end public class SetOperations.
SetTextLauncher class - reads from a text file
and implements the set operations
// Imported
packages.=============================================
===========
import java.util.*;
import java.io.*;
// Public class
SetTestLauncher.======================================
=======
public class SetTestLauncher
// Main method public static void main(String
g args[]).===================
     public static void main(String args[])
displayFile("test.txt"); // outputs result from
om text file.
     // method to display a file on screen
     public static void displayFile (String textFile)
// Instance
ce
variables.============================================
===
          // Creates new instances of SetOperations.
          SetOperations setA = new SetOperations();
          // Initialisation.
          String line = "", nextLine = "";
          FileReader fr = null;
          try
// Opens the file with the FileReader data sink
ink stream.
               fr = new FileReader(textFile);
// Converts the FileReader input stream with the
the BufferedReader processing stream.
               BufferedReader br = new BufferedReader(fr);
// Iterates through text file reading lines until
til end of text lines.
               while (line != null)
line = br.readLine(); // reads one line at a
at a time.
if(line == null) break; // when the line is null
null break the loop.
                    // Creates a new instace of StringTokenizer.
                    StringTokenizer st = new StringTokenizer(line);
                    // Loops until there are no more tokens.
                    while (st.hasMoreTokens())
String token = st.nextToken(); // reads next
next token.
// Only if the token encounters the String
tring "membera".
                         if(token.equals("membera"))
                              // *****THE PROBLEM LIES HERE....I GUESS
// need to read the next line after encountering the word membera in text file
nextLine = br.readLine(); // gets next line.
setA.addMember(nextLine); // adds a member to
ber to the set.
// Displays members present in the set if
set if vector is not empty.
                              if (! setA.isSetEmpty())
                                   setA.printMember(); // print members present.
// Displays the number of member/s present in
ent in the vector.
System.out.println("Number of set members: " +
s: " + setA.countMember());
          // Catches and displays exceptions.
          catch (FileNotFoundException exp)
               System.out.println(exp.getMessage());
               exp.printStackTrace();
          catch (IOException exp)
               System.out.println(exp.getMessage());
               exp.printStackTrace();
          finally
               try
                    // if file is found
                    if (fr != null)
                         // close file
                         fr.close();
               catch (IOException exp)
                    exp.printStackTrace();
     } // end public static void main(String args[]).
} // end public class SetTestLauncher.

SQL Loader-How to insert -ve & date values from flat text file into coloumn

Question: How to insert -ve & date values from flat text file into coloumns in a table.
Explanation: In the text file, the negative values are like -10201.30 or 15317.10- and the date values are as DDMMYYYY (like 10052001 for 10th May, 2002).
How to load such values in columns of database using SQL Loader?
Please guide.

Question: How to insert -ve & date values from flat text file into coloumns in a table.
Explanation: In the text file, the negative values are like -10201.30 or 15317.10- and the date values are as DDMMYYYY (like 10052001 for 10th May, 2002).
How to load such values in columns of database using SQL Loader?
Please guide. Try something like
someDate    DATE 'DDMMYYYY'
someNumber1      "TO_NUMBER ('s99999999.00')"
someNumber2      "TO_NUMBER ('99999999.00s')"Good luck,
Eric Kamradt

How do you read data from a text file into a JTextArea?

I'm working on a blogging program and I need to add data from a text file named messages.txt into a JTextArea named messages. How do I go about doing this?

Student_Coder wrote:
1) Read the file messages.txt into a String
2) Initialize messages with the String as the textSwing text components are designed to use Unix-style linefeeds (\n) as line separators. If the text file happens to use a different style, like DOS's carriage-return+linefeed (\r\n), it needs to be converted. The read() method does that, and it saves the info about the line separator style in the Document so the write() method can re-convert it.
lethalwire wrote:
They have 2 different ways of importing documents in this link:
http://java.sun.com/docs/books/tutorial/uiswing/components/editorpane.html
Neither of those methods applies to JTextAreas.

How to read some records from a text file into java(not all records)

hello,
how to read text files into java. i need only few records from the text file not all records at a time.
If any one knows plz reply me
my id is [email protected]

this snipet reads a text file line by line from line 1 to 3
try {
              FileReader fr = new FileReader(directory);
              BufferedReader br = new BufferedReader(fr);
              int counter = 0;
              while ((dbconn = br.readLine()) != null) {
                  switch(counter){
                      case 0:
                        status = dbconn;
                      break;
                      case 1:
                        userName = dbconn;
                      break;
                      case 2:
                        apword = dbconn;
                      break;
                  counter++;
              br.close();
    }catch(IOException e){
    }

Reading data from a text file into PAS - Dimension member names truncated

Hi,
I created a procedure to dump variables and data into a text file to load into another model. I used a semicolon as a field seperator.
The data, measures and dimension members are dumped properly into a text file and no dimension member names are truncated .
However when I read the data into a measure, and I issue a peek command, dimension meber names are read in truncated
and remain full names in the text file. Any reason for this? What do I need to do to prevent this from happening?
THanks.
Lungile

Hi Lungile,
The problem that you're likely having is that you haven't created a file description for the file from which you're reading. When loading data into Application Server from a text file, you would normally go through three steps:
1. Enter the ACCESS EXTERNAL subsystem
2. Specify the name of the file to be read
3. Specify the format of the file field names, types, widths, and positions.
If you go into the Application Server help, select "Application Server Help", then "Application Server at the command level", then "Variables and reading in data", and then "Reading an external file", you will have the process of the steps you need to follow outlined for you, including links to the help topic for each command you need to issue.
So what I think you need to do is use the DESCRIPTION command to specify the names of your fields, their type, and also their width, in order to ensure no truncation of data on the load.
The same DESCRIPTION statement is required if you want to use your text file as the source of a dimension.
Hope this helps,
Robert

Reading variables from a text file into a flash projector exe

I am using Flash CS4 and my script is in ActionScript2.
I am developing a flash projector file that runs when a user puts in a cd to guide them through the steps they need to install a program and then kicks off the installer.
I use fscommand to run a utility that reads the users registry to determine the PCs regional settings and then writes this to a text file in the users %temp% directory.
I then use the LoadVariablesNum command to read in the text file and get the variables.
This was working fine when I had the text file stored in a different directory, but when I try and refer to the %temp% directory, I get an Error opening file message.
Is there anyway to get flash to look in the %Temp% directory?
Thanks in advance,
Carol Lutz

Code-tags sometimes cause wonders, I replaced # with *, as the code tags interprets # as comment, which looks odd:
******...*.........To your code: Did you test it step by step, to find out about what is read? You could either use a debugger (e.g., if you have an IDE) or system outs to get a clue. First thing to check would be, if the maze size is read correctly. Further, the following loops look odd:for(int i = 0; i < maze.length; i++) {
    for(int x = 0; x < maze.length; x++) {
        if (input.hasNextLine()) {
            String insert = input.nextLine();
            maze[x] = insert.charAt(x);
}Shouldn't the nextLine test and assignment be in the outer loop? And assignment be to each maze's inner array? Like so:for(int i = 0; i < maze.length; i++) {
    if (input.hasNextLine()) {
        String insert = input.nextLine();
        for(int x = 0; x < insert.size(); x++) {
            maze[i][x] = insert.charAt(x);
}Otherwise, only one character per line is read and storing a character actually should fail.

How to import data from a text file into a table

Hello,
I need help with importing data from a .csv file with comma delimiter into a table.
I've been struggling to figure out how to use the "Import from Files" wizard in Oracle 10g web-base Enterprise Manager.
I have not been able to find a simple instruction on how to use the Wizard.
I have looked at the Oracle Database Utilities - Overview of Oracle Data Pump and the Help on the "Import: Files" page.
Neither one gave me enough instruction to be able to do the import successfully.
Using the "Import from file" wizard, I created a Directory Object using the Create Directory Object button. I Copied the file from which i needed to import the data into the Operating System Directory i had defined in the Create Directory Object page. I chose "Entire files" for the Import type.
Step 1 of 4 is the "Import:Re-Mapping" page, I have no idea what i need to do on this page. All i know i am not tying to import data that was in one schema into a different schema and I am not importing data that was in one tablespace into a different tablespace and i am not R-Mapping datafiles either. I am importing data from a csv file.
For step 2 of 4, "Import:Options" page, I selected the same directory object i had created.
For step 3 of 4, I entered a job name and a description and selected Start Immediately option.
What i noticed going through the wizard, the wizard never asked into which table do i want to import the data.
I submitted the job and I got ORA-31619 invalid dump file error.
I was sure that the wizard was going to fail when it never asked me into which table do i want to import the data.
I tried to use the "imp" utility in command-line window.
After I entered (imp), i was prompted for the username and the password and then the buffer size as soon as i entered the min buffer size I got the following error and the import was terminated:
C:\>imp
Import: Release 10.1.0.2.0 - Production on Fri Jul 9 12:56:11 2004
Copyright (c) 1982, 2004, Oracle. All rights reserved.
Username: user1
Password:
Connected to: Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - Produc
tion
With the Partitioning, OLAP and Data Mining options
Import file: EXPDAT.DMP > c:\securParms\securParms.csv
Enter insert buffer size (minimum is 8192) 30720> 8192
IMP-00037: Character set marker unknown
IMP-00000: Import terminated unsuccessfully
Please show me the easiest way to import a text file into a table. How complex could it be to do a simple import into a table using a text file?
We are testing our application against both an Oracle database and a MSSQLServer 2000 database.
I was able to import the data into a table in MSSQLServer database and I can say that anybody with no experience could easily do an export/import in MSSQLServer 2000.
I appreciate if someone could show me how to the import from a file into a table!
Thanks,
Mitra

>
I can say that anybody with
no experience could easily do an export/import in
MSSQLServer 2000.
Anybody with no experience should not mess up my Oracle Databases !

Reading from a text file into a 2D array

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