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Re: How to make an array in text file (help..)

Quote:

Originally Posted by javaAddict (Post 738590)

I have tried this:

public static void main(String[] args) {

                BufferedReader lnr = null;

                String line = null;

                try {

                        lnr = new BufferedReader (new FileReader("accountList.txt"));

                        for (line = lnr.readLine(); line!=null; line = lnr.readLine()) {

        

                                String account[] = line.split(" ");

                                

                                System.out.println(account[0]);

                        }

                        

                        lnr.close();

                } catch (Exception e) {

                        System.out.println("An error has occured: "+e.getMessage());

                        //e.printStackTrace();

                }

        }

The file has these:

And it printed:

12345
55555

what if i will only print out the:

12345???

it seems that the 55555 was printed out also because it was stored in [0] array...so i think,,it should be;;

account[1][0] so that it will only print the 12345.....

and i am really confused either,,,on how to do it....i am not that good in text file really...

Re: How to make an array in text file (help..)

It was printed because it was the accountId of the second line of the file. You are the one who wrote the code that loops through each line of the file:

for (....) {

}

With the above code you loop each line and get the values from each line:
account[0], account[1], account[2], ....

Why would you have it any other way? What would be the point of getting only the first line and not the rest of the lines of the files?

Now if you want to store the entire file in a single array, then Yes, use a 2-D array:

int N=1000;

String [][] array = new String[N][]

....

....

int count=0;

for (....) {



array[count] = line.split(" ");

count++;

}

I don't know if the above will work. You might want to test it.
If it doesn't then declare the 2-D array: [N][5] and in the loop take the line in a different 1-D array and put the values in the 2-D array.

Re: How to make an array in text file (help..)

I have tested and here is an example:

public static void main(String[] args) {

                BufferedReader lnr = null;

                String line = null;

                

                int N=1000;

                int totalRecords = 0;

                

                String [][] array = new String[N][];

                

                try {

                        lnr = new BufferedReader (new FileReader("accountList.txt"));



                        for (line = lnr.readLine(); line!=null; line = lnr.readLine()) {

        

                                array[totalRecords] = line.split(" ");

                                totalRecords++;

                        }

                        

                        lnr.close();

                } catch (Exception e) {

                        System.out.println("An error has occured: "+e.getMessage());

                        //e.printStackTrace();

                }

                for (int i=0;i<totalRecords;i++) {

                        for (int j=0;j<array[i].length;j++) {

                                System.out.print(array[i][j]+" ");

                        }

                        System.out.println();

                }

        }

2-D arrays in java don't exist. Actually what you do is create a single array and each element has another array:

String [][] array = new String[N][]; //2-D array with N rows



array[totalRecords] = line.split(" "); // the row: totalRecords will have the array returned by the split method.

So the

array[totalRecords]

has another array inside it and to access it you do:
array[totalRecords][0],
array[totalRecords][1],
array[totalRecords][2]

You initiall set the max row to be N=1000 because you don't know the size of the file. But you use the totalRecords variable to count the lines, because inside the loop you don't an int variable so you must do:
array[totalRecords] = ...
totalRecords++

in order to place the next line to the next row.

When you print the values you don't use the N at the first loop because not all rows of the array have value. You use the totalRecords. Remember you have used to count the lines read in the first loop.
The second inner loop you say:

array[i].length

because the array[i] is also a single array and in the inner loop you print its values:
array[i][0], array[i][1] : array[i][j]

Re: How to make an array in text file (help..)

Quote:

Originally Posted by javaAddict (Post 738636)

I have tested and here is an example:

public static void main(String[] args) {

                BufferedReader lnr = null;

                String line = null;

                

                int N=1000;

                int totalRecords = 0;

                

                String [][] array = new String[N][];

                

                try {

                        lnr = new BufferedReader (new FileReader("accountList.txt"));



                        for (line = lnr.readLine(); line!=null; line = lnr.readLine()) {

        

                                array[totalRecords] = line.split(" ");

                                totalRecords++;

                        }

                        

                        lnr.close();

                } catch (Exception e) {

                        System.out.println("An error has occured: "+e.getMessage());

                        //e.printStackTrace();

                }

                for (int i=0;i<totalRecords;i++) {

                        for (int j=0;j<array[i].length;j++) {

                                System.out.print(array[i][j]+" ");

                        }

                        System.out.println();

                }

        }

2-D arrays in java don't exist. Actually what you do is create a single array and each element has another array:

String [][] array = new String[N][]; //2-D array with N rows



array[totalRecords] = line.split(" "); // the row: totalRecords will have the array returned by the split method.

So the

array[totalRecords]

array[i].length

because the array[i] is also a single array and in the inner loop you print its values:
array[i][0], array[i][1] : array[i][j]

oh,,i am sorry if i have read your reply too late...thank you very much for your help,,thank you very much,,,,ok,, i will do everything you told me,,it seems that i am too busy...thank you very much for the help....(^.^)