Getting specific row and column value in .csv file in c#

Question

I have a .csv file that looks like this:

Index,Time,value
1,0,20
2,1,30

What I want to do is to open the .csv file in C# and then read it by getting row = 0, column = 0 which would give me value 1 in the case above. Much like this:

public double GetVal(int row, int column)
{
 ...
 return val;
}

I have looked around for a solution, for example this one: Remove values from rows under specific columns in csv file

But I need to be able to specify both the column and row in the function to get the specific value.

Take a 3r party library joshclose.github.io/CsvHelper/examples/reading/…. then you will have a list object where you can nagivate using index and property name. Really more usefull that row and column. And read the file only once. — Drag and Drop
– Drag and Drop, Commented Mar 4, 2020 at 9:52
There's actually a CSV parser in .Net natively; the TextFieldParser in the VisualBasic namespace. — Nyerguds
– Nyerguds, Commented Mar 4, 2020 at 13:49

Dmitrii Bychenko · Accepted Answer · 2020-03-04 14:00:48Z

2

In case CSV file is simple one (no quotations), you can try Linq:

using System.IO;
using System.Linq;

...

public double GetVal(int row, int column) {
  return File
    .ReadLines(@"c:\MyFile.csv") //TODO: put the right name here
    .Where(line => !string.IsNullOrWhiteSpace(line)) // to be on the safe side
    .Skip(1)   // Skip line with Titles
    .Skip(row)
    .Select(line => double.Parse(line.Split(',')[column]))
    .First();
}

Note, that this code re-reads the file; you may want to read the file once:

  string[][] m_Data = File
    .ReadLines(@"c:\MyFile.csv")
    .Where(line => !string.IsNullOrWhiteSpace(line)) 
    .Skip(1)
    .Select(line => line.Split(','))
    .ToArray();

  ...

  public double GetVal(int row, int column) => double.Parse(m_Data[row][col]);

edited Mar 4, 2020 at 14:00

answered Mar 4, 2020 at 9:52

Dmitrii Bychenko

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4 Comments

KGB91 Over a year ago

I tested the latter one and it gives me "System.FormatException: 'Input string was not in a correct format.'".

Dmitrii Bychenko Over a year ago

@KGB91: System.FormatException is thrown when string doesn't meet expected format, e.g. when we double.Parse on a string which can't be converted into double ("abcdef" and alike)

KGB91 Over a year ago

Can't I just everything as a string and then convert it to a double if I want to?

Dmitrii Bychenko Over a year ago

@KGB91: yes, we can postpone double.Parse which we can perform at GetVal

dlxeon · Accepted Answer · 2020-03-04 09:46:46Z

0

Although you can write simple code by yourself, I would suggest you using dedicated CSV library for this like https://www.nuget.org/packages/LumenWorksCsvReader/ There are tons of edge cases like values escaping with double quotes, multiline values in CSV file format.

But if you totally control your files and they are small, you can read all lines at once and parse them. Something like this to get all lines from file and then split every line by ',' character

var lines = File.ReadAllLines('your file');

answered Mar 4, 2020 at 9:46

dlxeon

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Comments

David · Accepted Answer · 2020-03-04 09:51:37Z

0

Quick answer, without considering the performance issue (e.g. the file read should happen once, and other issue like index checking to avoid overflows.

public double GetVal(int row, int column) 
{
    double output;
    using (var reader = new StreamReader("filename.csv"))
    {
        int m = 1;
        while (!reader.EndOfStream)
        {
            if(m==row)
            {
                var splits = rd.ReadLine().Split(',');
                //You need check the index to avoid overflow
                output = double.Parse(splits[column]);
                return output;
            }

            m++;
        }
    }
    return output;
}

answered Mar 4, 2020 at 9:51

David

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