Convert string from text file to integer array

Question

I wrote this code in order to open a text file in a C# language Each line in the file contains five digits such as

0    0    2    3     6

0    1    4    4     7

0    2    6    9     9

1    0    8    11    9

1    1    12   15    11

2    2    12   17    15

The distance between the number and the other is one tab The problem is when you execute the program this error appears

input string was not in correct format in Convert.ToInt32(t[j])

code:

string[] st = File.ReadAllLines("C:\\testing\\result.txt");
int[,] tmp = new int[st.Length - 1, 5];
for (int i = 1; i < st.Length; i++)
{

   string[] t = st[i].Split(new char[] { ' ' });
   int cnt = 0;
   for (int k = 0; k < t.Length; k++)
        if (t[k] != "")
           { t[cnt] = t[k]; cnt++; }
        for (int j = 0; j < 5; j++)
                tmp[i - 1, j] = Convert.ToInt32(t[j]);
 }

How can i correct that?

Hint: use braces everywhere. It'll make it a lot clearer. You currently appear to be under the impression that your second for loop is nested inside your first. It isn't. — Jon Skeet
– Jon Skeet, Commented May 15, 2017 at 8:40
The error 'input string was not in correct format in Convert.ToInt32(t[j])' appears when the input to Convert.ToInt32 doesn't contain any number. How about setting a breakpoint there and checking the value of t[j]? — degant
– degant, Commented May 15, 2017 at 8:42

Dmitrii Bychenko · Accepted Answer · 2017-05-15 08:54:55Z

8

I suggest changing the collection type from 2d array int[,] into jagged one int[][] and then use Linq:

 using System.Linq;

 ...

 int[][] data = File
   .ReadLines(@"C:\testing\result.txt")
   .Select(line => line
       // Uncomment this if you have empty lines to filter out:
       // .Where(line => !string.IsNullOrWhiteSpace(line)) 
      .Split(new char[] {'\t'}, StringSplitOptions.RemoveEmptyEntries)
      .Select(item => int.Parse(item))
      .ToArray())
   .ToArray();

edited May 15, 2017 at 8:54

answered May 15, 2017 at 8:42

Dmitrii Bychenko

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Dmitrii Bychenko · Accepted Answer · 2017-05-15 09:09:25Z

1

split char should be a tab character '\t' instead of single space

edited May 15, 2017 at 9:09

Dmitrii Bychenko

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answered May 15, 2017 at 8:45

Bhuban Shrestha

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1 Comment

zozo Over a year ago

@Dmitry Bychenko,@ Bhuban: Thank you

Lajos Arpad · Accepted Answer · 2017-05-15 09:49:53Z

You have five numbers per row, but not necessarily five digits. You will need a more complex solution, like this:

string[] st = File.ReadAllLines("C:\\testing\\result.txt");
int[,] tmp = new int[st.Length - 1, 5];
bool isAlreadyNumber = false;
bool isEmptyRow = true;
int rowIndex = -1;
int colIndex = -1;
for (int i = 0; i < st.Length; i++) {
   isAlreadyNumber = false;
   isEmptyRow = true;
   foreach (char c in st[i]) {
      if ((c >= '0') && (c <= '9')) {
          if (isAlreadyNumber) {
              tmp[rowIndex][colIndex] = tmp[rowIndex][colIndex] * 10 + (c - '0');
          } else {
              tmp[rowIndex][colIndex] = c - '0';
              if (isEmptyRow) rowIndex++;
              isEmptyRow = false;
              isAlreadyNumber = true;
          }
      } else {
          isAlreadyNumber = false;
      }
   }
 }

Note, that the indexing was fixed. This untested code handles other separators and empty lines as well, but still assumes there will be five numbers.

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