How to read characters from a text file in java program ?

Sir,
I have to read the characters m to z listed in a text file .
I must compare the character read from the file.
And if any of the characters between m to z is matched i have to replace it with a hexadecimal value.
Any help or suggesstions in this regard would be very useful.
Thanking you,
khurram

Hai,
The requirement is like this
There is an input file, the contents of the file are as follows, you can assume any name for the file.
#Character mappings for Japanese Shift-JIS character set
#ASCII character Mapped Shift-JIS character
m 227,128,133 #Half width katakana letter small m
n 227,128,134 #Half width katakana letter small n
o 227,129,129
p 227,129,130
q 227,129,131
r 227,129,132
s 227,129,133
t 227,129,134
u 227,129,135
v 227,129,136
w 227,129,137
x 227,129,138
y 227,129,139
z 227,129,142
The contents of the above file are to be read as input.
On encountering any character between m to z, i have to do a replacement with a hexadecimal code point value for the multibyte representation in the second column in the input file.
I have the code to get the unicode codepoint value from the multibyte representation, but not from a file.
So if you could please tell me how to get the characters in the second column, it would be very useful for me.
The character # is used to represent the beginning of a comment in the input file.
And comment lines are to be ignored while reading the file.
Say i have a string str="message";
then i should replace the m with the unicode code point value.
Thanking you,
khurram

Similar Messages

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.

How to read data from a text file

I have saved a text file on my hard drive, and would like to read the file. Once read I would like to copy it to another file. I think I am suppose to use the BufferedReader, and FileReader classes. I am not sure what sequence to follow in order to do this. Could some one give me some feed back on what is needed, and in what sequence to perform this task?

Where do I store my file within my Platform(Eclipe), in order to read or access the file. Whenever I use the declaration below. I get an FileNotFoundException. I understand the code, but am not sure where to store the file, so that the line of code below will recognize it..
FileReader in = new FileReader("data1.txt");
BufferedReader a = new BufferedReader(in);

How to read data from the excel file using java code.

Hi to all,
I am using below code to getting the data from the excel file but I can't get the corresponding data from the specific file. can anyone give me the correct code to do that... I will waiting for your usefull reply......
advance thanks....
import java.io.*;
import java.sql.*;
    public class sample{
             public static void main(String[] args){
                  Connection connection = null;
                      try{
                           Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
                           Connection con = DriverManager.getConnection( "jdbc:odbc:Mydsn","","" );
                           Statement st = con.createStatement();
                           ResultSet rs = st.executeQuery( "Select * from [Sheet1$]" );
                           System.out.println("sample:"+rs);
                              ResultSetMetaData rsmd = rs.getMetaData();
                              System.out.println("samplersd:"+rsmd);
                           int numberOfColumns = rsmd.getColumnCount();
                              System.out.println("numberOfColumns:"+numberOfColumns);
                               while (rs.next()) {
                                        System.out.println("sample1:"+rs);
                                        for (int i = 1; i <= numberOfColumns; i++) {
                                             if (i > 1) System.out.print(", ");
                                             String columnValue = rs.getString(i);
                                             System.out.print(columnValue);
                                        System.out.println("");
                                   st.close();
                                   con.close();
                                  } catch(Exception ex) {
                                       System.err.print("Exception: ");
                                       System.err.println(ex.getMessage());
                    }

1: What is the name of the excel sheet?
2: What is printed in this program? null ? anything?
error?Excel file name is "sample.xls" I set excel file connectivity in my JDBC driver(DSN). Here in my program I am not giving that excel file name. I am giving only that excel sheet name. that is followed
ResultSet rs = st.executeQuery( "Select * from [Sheet1$]" );The output of this program is given bellow.
sample:sun.jdbc.odbc.JdbcOdbcResultSet@1b67f74
samplersd:sun.jdbc.odbc.JdbcOdbcResultSetMetaData@530daa
numberOfColumns:2

Read data from a text file, one line at a time.

I need to read data from a text file, and display each line in a String Indicator on Front Panel. It displays each line, but I get Error 4, End Of Line, unless I enter an extra line of data in the file that I don't need. I tried Read From Text File.vi, made by Nat Instr, and it gave the same error.

The Read from Text File.vi reads data from a text file line by line until the user stops the VI manually with the Stop button on the front panel, or until an error (such as "Error 4, End of file") occurs. If an error occurs, the Simple Error Handler.vi pops up a dialog that tells you which error occurred.
The Read from Text File.vi uses a while loop, but if you knew how many lines you wanted to read, you could replace the while loop with a for loop set to read that many lines from the file.
If you need something more dynamic because the number of lines in your files vary, then you could change the code of the Read from Text File.vi to the expect "Error 4, End of file" and handle it appropriately. This would require unbundling the error cluster that comes fro
m the Read File function with the Unbundle By Name function, so that you can expose the individual error "status" and error "code" values stored in the cluster. If the value of the error "code" is 4, then you can change the error "status" from true to false, and you can rebundle the cluster with the Bundle by Name function. Setting the error "status" to false instructs the Simple Error Handler to ignore the error. Otherwise, pass the original error cluster to the Simple Error Handler.vi, so that you can see what the error is.
Of course, if you're not interested in what the errors are, you could just remove the Simple Error Handler.vi, but then you wouldn't see any error messages.
Best of Luck,
Dieter
Dieter Schweiss
Applications Engineer
National Instruments

Need to read data from a text file

I need to read data from a text file and create my own hash table out of it. I'm not allowed to use the built in Java class, so how would I go implementing my own reading method and hash table class?

It's not possible to read from a file without using classes from the core API*. You'll have to get clarification from your instructor as to which classes are and are not allowed.
[http://java.sun.com/docs/books/tutorial/essential/io/]
*Unless you write a bunch of JNI code to replicate what the java.io classes are doing.

Removing the Control Characters from a text file

Hi,
I am using the java.util.regex.* package to removing the control characters from a text file. I got below programming from the java.sun site.
I am able to successfully compile the file and the when I try to run the file I got the error as
------------------------------------------------------------------------D:\Debi\datamigration>java Control
Exception in thread "main" java.util.regex.PatternSyntaxException: Illegal repet
ition
{cntrl}
at java.util.regex.Pattern.error(Pattern.java:1472)
at java.util.regex.Pattern.closure(Pattern.java:2473)
at java.util.regex.Pattern.sequence(Pattern.java:1597)
at java.util.regex.Pattern.expr(Pattern.java:1489)
at java.util.regex.Pattern.compile(Pattern.java:1257)
at java.util.regex.Pattern.<init>(Pattern.java:1013)
at java.util.regex.Pattern.compile(Pattern.java:760)
at Control.main(Control.java:24)
Please help me on this issue.
Thanks&Regards
Debi
import java.util.regex.*;
import java.io.*;
public class Control {
public static void main(String[] args)
throws Exception {
//Create a file object with the file name
//in the argument:
File fin = new File("fileName1");
File fout = new File("fileName2");
//Open and input and output stream
FileInputStream fis =
new FileInputStream(fin);
FileOutputStream fos =
new FileOutputStream(fout);
BufferedReader in = new BufferedReader(
new InputStreamReader(fis));
BufferedWriter out = new BufferedWriter(
new OutputStreamWriter(fos));
// The pattern matches control characters
Pattern p = Pattern.compile("{cntrl}");
Matcher m = p.matcher("");
String aLine = null;
while((aLine = in.readLine()) != null) {
m.reset(aLine);
//Replaces control characters with an empty
//string.
String result = m.replaceAll("");
out.write(result);
out.newLine();
in.close();
out.close();

Hi,
I used the code below with the \p, but I didn't able to complie the file. It gave me an
D:\Debi\datamigration>javac Control.java
Control.java:24: illegal escape character
Pattern p = Pattern.compile("\p{cntrl}");
^
1 error
Please help me on this issue.
Thanks&Regards
Debi
// The pattern matches control characters
Pattern p = Pattern.compile("\p{cntrl}");
Matcher m = p.matcher("");
String aLine = null;

How to parse data from a text file with no convenient delimiters?

I need to read data from a text file. This file contains one line of data with the repeating pattern "time 00 ADVar2: ___ Height: ____ time 01 ADVar2: ___ Height: ___ ..." I need LabView to parse out the "time" and "height" values, build an array with the values, and graph the correlation on an X&Y plot. Does Labview have an automated way to read to the input data file and parse out the correct values, even without convenient delimiters? Thank you.

You actually do have a convenient delimiter: "time". Thus, you can make an array using that as the delimiter. Only caveat is that the first array element will be empty. Then you can conveniently use the Scan From String function in a for-loop. Something like this:
Message Edited by smercurio_fc on 11-21-2008 03:13 PM
Attachments:
Example_VI.png ‏9 KB

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){
    }

How to read some lines from a text file using java.

hi,
i m new to java and i want to read some lines from a text file based on some string occurrence in the file. This file to be read in steps.
we only want to read the file upto the first Occurrence of "TEXT" string.
How to do it ,,,
Kinldy give the code
Regards,
Sagar
this is the text file
dfgjdjj
sfjhjkd
ghjkdg
hjkdgh TEXT
ikeyt
ujt
jk
tyk TEXT
rukl
r

Hendawy wrote:
Since the word "TEXT" is formed of 4 letters, you would read the text file 4 bytes by four bytes. Wrong on two counts. First, the file may not be encoded 1 byte per character. It could be utf-16 in which case it would be two byte per character. Second, even if it were 1 byte per character, the string "Text" may not start on a 4 byte boundary.
Consider a FileInputStream object "fis" that points to your text file. use fis.read(byte[] array, int offset, int len) to read every four bytes. Convert the "TEXT" String into a byte array "TEXT".getBytes(), and yous the Arrays class to compare the equality of the read bytes with your "TEXT".getBytes()Wrong since it relies on my second point and will fail when fis.read(byte[] array, int offset, int len) does not read 4 bytes (as is no guaranteed to). Check the Javadoc. Also, the file may not be encoded with the default character encoding.
The problem is easily solved by reading a line at a time using a BufferedReader wrapping an InputStreamReader wrapping a FileInputStream and specifying the correct character encoding.
Edited by: sabre150 on Apr 29, 2009 2:13 PM

I need to read data from a text file and display it in a datagrid.how can this be done..please help

hey ppl
i have a datagrid in my form.i need to read input(fields..sort of a database) from a text file and display its contents in the datagrid.
how can this be done.. and also after every few seconds reading event should be re executed.. and that the contents of the datagrid will keep changing as per the changes in the file...
please help as this is urgent and important.. if possible please provide me with an example code as i am completely new to flex...
thanks.....

It's not possible to read from a file without using classes from the core API*. You'll have to get clarification from your instructor as to which classes are and are not allowed.
[http://java.sun.com/docs/books/tutorial/essential/io/]
*Unless you write a bunch of JNI code to replicate what the java.io classes are doing.

How to save input from a text file in to array

I got this assignment, and almost have no clue, and my teacher doesn't even teaches us anything
This is what i am suppose to do
5. The program must store the following data about each student in this Talent Show:
* The student's name (store as a String)
* The student's average time score [only for the events they competed in] (store as a Double)
Note: Some of the data comes directly from the text file, and some of the data must be calculated from the data that is read from the file.
6. The program must search through all of the student's scores to find the student who has the minumum average time of all students.
7. You must calculate how many events each student played. Zero values are not counted.
8. You must then generate a report on the screen that prints out
* the total number of students in the competition,
* the winning student's ...
o name
o times
o average time (rounded to one decimal places)
Sample output
btw this is the data file
Bart Simpson
7.5
12.3
7.8
19.2
9.9
5.3
8.5
11.8
2.2
4.6
Stewie Griffin
9.5
29.7
7.8
22.5
9.9
12.6
8.5
0
8.2
0
Pinky
2.5
0
1.8
0
3.9
0
6.5
0
5.2
12.1
Rocky N Bullwinkle
10.0
22.2
9.5
17.5
9.9
1.5
8.7
23.7
9.2
11.0
Angelica Pickles
5.5
11.1
6.8
12.2
7.9
13.3
8.1
5.1
7.2
7.9
Pink Panther
8.5
5.5
8.8
6.6
8.9
7.7
9.9
8.8
2.2
9.9
Josie
9.5
0
8.8
12.2
9.9
0
8.5
0
9.2
5.3
Rogue
8.5
1.1
7.8
2.2
7.9
3.3
7.5
4.4
8.2
5.5
Usagi Tsukino
8.5
15.5
8.8
30.1
9.9
19.7
9.5
11.0
8.2
8.6
Yosemite Sam
0
15.2
0
29.5
3.9
0
0
16.0
0
7.7
My code so far
import java.io.*;
public class test
    public static void main (String [] args)
        FileInputStream File1;
        DataInputStream In;
        String fileInput = "";
        try
           File1 = new FileInputStream ("data.txt");
            In = new DataInputStream (File1);
            while (In.available () > 0)
                fileInput = In.readLine ();
                System.out.println (fileInput);
            In.close ();
        catch (FileNotFoundException e)
            System.out.println ("Error - this file does not exist");
        catch (IOException e)
            System.out.println ("error=" + e.toString ());
}My question, how do i save the data in to an array, and how do i seperatly save names in to different array, and their scores in to different arrays
bte he said you can use scanner class
Thanks
Edited by: supahsain08 on Mar 26, 2008 2:55 PM

supahsain08 wrote:
Well, you are not in my class and you don't even know my teacher
who are you to judge meHe is jaded by our experiences here. 99% of posters who complain that the teacher doesn't teach have adequate (note that I didn't say good) teachers, but it's the student who is failing to take responsibility for his own education. It is after all your responsibility and complaining won't help you any.
Good luck.

How to execute code from a text file?

Hello all!
How to execute some code lines from a text file? For example my file is:
String varname = "somecontents";
JFrame frame = new JFrame();
frame.setVisible(true);How can I get contents of this file and parse them if I want get new JFrame and access to the variable varname?

I mean the PHP would generate a readable Java source,
for example some variables with some data, and I just
dont know what to do with file if I want generate the
xls file from my saved data, could You help? :)Some variables, some data, PHP, Java, XLS file??? Al rather vague.
You need to explain in more detail what it is you're trying to do if you want an answer to your question!

Help! How to read data from an Excel file?

Hi,
I need to read data from an Excel file that may contain more then one table in a sheet. How can I read them?
I would be eternally grateful to anyone who can give me any information.

Did you try POI from Apache?
http://jakarta.apache.org/poi/index.html

How to read characters from a text file in java program ?

Similar Messages

Maybe you are looking for