How to perform a text search on a column inside a CSV file with C#?

Question

I'm trying to perform a search on a column inside a CSV file, but cannot for the life of me figure out the best way to do it. I'm quite new to C# so most things I found were quite complicated.

The CSV file has three columns "id", "title" and "rating", and I want to search trough the title column.

I cam across a suggestion that I should turn the CSV into a list and then search through it.

This is the code I have so far for converting the file into a list:

var reader = new StreamReader(File.OpenRead(@"books.csv"));
            List<string> listA = new List<string>();
            List<string> listB = new List<string>();
            while (!reader.EndOfStream)
            {
                var line = reader.ReadLine();
                var values = line.Split(';');

                listA.Add(values[0]);
                listB.Add(values[1]);

                foreach (var column1 in listA)
                {
                    Console.WriteLine(column1);
                }

                foreach (var column2 in listA)
                {
                    Console.WriteLine(column2);
                }
            }

But I do not understand how it works and I get an error

Index was outside the bounds of the array

Could anybody point me in the right direction because I'm quite lost?

Answer 1

If you're using StreamReader, then you do not need to call File.OpenRead (as the StreamReader can handle this and it will alter the encoding of your data).

You're reading a csv (Comma-separated values) file, but you're doing a split on semi-colon. (You can check this, by opening your csv file in notepad).

Also you do a split, but you not check if there are 2 items. So values[1] can throw an Index was outside the bounds of the array error.

As a starting point try:

var listA = new List<string>();
var listB = new List<string>();

using (var reader = new StreamReader(@"books.csv"))
{
    while (!reader.EndOfStream)
    {
        var line = reader.ReadLine();
        if (!string.IsNullOrEmpty(line))
        {
            var values = line.Split(',');

            if (values.Length > 1)
            {
                listA.Add(values[0]);
                listB.Add(values[1]);
            }
        }
    }
}

As per the comments. A better way to write the code will be to use a third party package like CSV Helper (https://joshclose.github.io/CsvHelper).