Re-use a string array using the split method

[Joe Campanini]

I have a list of input strings and I want to take each string and using the split method populate a string array, do some stuff with it and that process is in a "for" loop. After each pass through the "for" loop I want to re-use the same string array. And, as all you fundi's in c# will know, the array just keeps getting added to. How do I say start from scratch each time? I know this is going to be real easy, and I'm going to feel real foolish once it is pointed out to me, but please point it out to me!!!!

[adriancs]

check this out. Possible duplicate question:
http://bytes.com/topic/c-sharp/answe...e-bounds-array

for string split method examples:
http://www.dotnetperls.com/string-split

[Joe Campanini]

Thanks Adriancs, but doesn't answer my question. It was using dotnetperls that gave me the idea to use the split method. Say that I read, using StreamReader, strings of data into memory:
a1 a2 a3
b1 b2 b3
c1 c2 c3 etc.

ArrayList rawData = new ArrayList();
try
{
  StreamReader readFile = new StreamReader(pathNames);
  while (line != null)
    {
      line = readFile.ReadLine(); 
      rawData.Add(line);
    }
  }
    catch (Exception f)
     {
       MessageBox.Show(f.Message);
     }
int rIn = rawData.Count;
for (int i = 0; i < rIn; i++)
     {
        string[] data = rawData[i].Split();
 
// Do a whole bunch of stuff, up to here everything works as expected
     }
 
// I get:
//       data[0] = "a1"
//       data[1] = "a2"
//       data[3} = "a3"
// However it's on the next iteration i = 1, I get the following
//       data[0] = "a1"
//       data[1] = "a2"
//       data[3} = "a3"
//       data[4] = "b1"
//       data[5] = "b2"
//       data[6} = "b3"
// And I just want
//       data[0] = "b1"
//       data[1] = "b2"
//       data[3} = "b3"
 
 

How do I tell my program to start filling ‘data’ array from '0' again?

[shilpa george]

Hello Joe ,
I am not sure if this works...
Declare the string array as
string[] data = null;
outside the for loop or try adding
data = null;
just before the closing brace of for loop.....

[Joe Campanini]

Hello Shilpa,

Thanks for trying, but no, it doesn't work. To be honest I had already tried the data = null rout inside the for loop, but this time I added the string data[] = null also, but without any success, but thank you for making the suggestion.

Joe

[adriancs]

well, perhaps there's some logic error occur somewhere at the unseen code.

I have try this, and it seems to be what you want.
you may need to double check your coding.

I have test the below with a text file.
The content of the text(D:\textfile.txt):

yellow blue green red
tea juice milk coffee
car bus lorry van

the code:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
 
    private void button1_Click(object sender, EventArgs e)
    {
        string line = "";
        string pathNames = "D:\\textfile.txt";
        ArrayList rawData = new ArrayList();
        try
        {
            StreamReader readFile = new StreamReader(pathNames);
            while (line != null)
            {
                line = readFile.ReadLine();
                rawData.Add(line);
            }
        }
        catch (Exception f)
        {
            MessageBox.Show(f.Message);
        }
        int rIn = rawData.Count;
        for (int i = 0; i < rIn; i++)
        {
            string[] data = (rawData[i] + "").Split(' ');
            string da = "";
            if (data.Length == 1 && data[0] == "") da = "Finish.";
            else
            {
                for (int j = 0; j < data.Length; j++)
                {
                    da += "data[" + j + "] = " + data[j] + "\n";
                }
            }
            MessageBox.Show(da);
        }
    }
}

[Fr33dan]

You have you debugged and verified the status of rawData? The code as you posted it throws away the data[] variable every time split is called, just as if you set an int from 3 to 5, the 3 is thrown out.

In order to get what you described the next instance of rawData must have the data from the previous in it:

rawData[0] = "a1,a2,a3"
rawData[1] = "a1,a2,a3,b1,b2,b3"
rawData[2] = "a1,a2,a3,b1,b2,b3,c1,c2,c3"

I have seen errors like this in reading text files when reusing the same variables when populating a data arrays.

Edit: seems adriancs and I were typing at the same time, but we're both getting at the same issue I think.

[adriancs]

You mean...you want to split all the strings and make it a string array?

private void button1_Click(object sender, EventArgs e)
{
    string line = "";
    string pathNames = "D:\\textfile.txt";
    ArrayList rawData = new ArrayList();
    try
    {
        StreamReader readFile = new StreamReader(pathNames);
        while (line != null)
        {
            string[] sa = line.Split(' ');
            foreach (string s in sa)
            {
                if (s != "")
                    rawData.Add(s);
            }
            line = readFile.ReadLine();
        }
    }
    catch (Exception f)
    {
        MessageBox.Show(f.Message);
    }
    string da = "";
    int rIn = rawData.Count;
    string[] data = new string[rIn];
    for (int i = 0; i < rIn; i++)
    {
        data[i] = rawData[i] + "";
        da += "data[" + i + "] = " + rawData[i] +"\n";
    }
    MessageBox.Show(da);
}

[adriancs]

duplicate post.
This post can be deleted.

[Joe Campanini]

Thanks guys, you have pointed me in the right direction, the code I didn’t show. Adrian, for brevity purposes I was not totally expicit, the actual code works on a split of a split. So, for the first split I also get the same result with the code I did not supply as you get with the code you supplied. It's when I get to the next step that I ran into the problem, and, as Hamlet say’s, therein lies the rub! I have been sticking the result of my first split into a string, and that code was wrapped in a #region/#endregion , and out of sight out of mind, I have not been clearing out the string from the first split. I think I am now going to hang myself :-)

[adriancs]

Hi, you have to mark "choose as best answer" button on the most appropriate post that has solved your problems. :-)

[Joe Campanini]

Sorry - Done :-) :-)