Using LINQ to read delimited text files

Did you ever face a situation where you want to read a delimited file (CSV or any similar format) and want to filter the records on the basis of some conditions (by checking some values against columns).

For example, let's assume that Data.txt file contains the following records:

Name,Age,City
Person1,30,CityA
Person2,20,CityB
Person3,25,CityB
Person4,30,CityA
Person5,27,CityA

If we want to find all records which belong to CityA with age >= 30 then we can use LINQ for this purpose:

string delimiter = ",;";
List<string> logs = (File.ReadAllLines(@"C:\Data.txt")
    // leave blank lines
    .Where(line => !string.IsNullOrEmpty(line))
    // split line seperated by delimiter
    .Select(line => line.Split(delimiter.ToCharArray(), StringSplitOptions.RemoveEmptyEntries))
    // compare the third column to find all records from CityA
    .Where(values => values[2].Equals("CityA", StringComparison.CurrentCultureIgnoreCase))
    // compare the second column to find all records with age more than or equal to 30
    .Where(values => int.Parse(values[1]) >= 30)
    // join back the splitted values by underscore
    .Select(values => string.Join("_", values))
    // find all unique values
    .Distinct()
    .ToList<string>());// convert to list

Hope this will help you out in reading delimited files :)

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This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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The Manoj Kumar

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Manoj Kumar is a Humble Programmer and a trainer having dozens of trainings, publications and articles to his wallet.

His programming adventures began with Basic at an age of 11. Being a mathematician at core, soon he started looking for some more and moved to assembly language, later to C, C++, VC++ and finally to .Net.

He started his professional career as a VC++ 6 trainer, moved to embedded systems and device driver development, then to complex biological systems and finally moved to pure application development.

He has been teaching and training people for more than 12 years on a wide range of topics including Mathematics, Algorithms, Data Structures, C, C++, VC++, MFC, C#, Design Patterns and now a days he is working extensively with Visual Studio and .Net framework which includes VSX, WPF, Silverlight, WCF, WF, XAML and RIAs.

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Did you ever face a situation where you want to read a delimited file (CSV or any similar format) and want to filter the records on the basis of some conditions (by checking some values against columns).For example, let's assume that Data.txt file contains the following...

Type	Tip/Trick
Licence	CPOL
First Posted	16 Mar 2010
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Using LINQ to read delimited text files

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