Parsing a text file to CSV using LINQ

Question

I am completely new to LINQ and I want to learn it's usefulness in parsing text files, instead of using a scripting language such as Perl or Ruby. I have generated a long list delimited by "CR" and "LF" and I would like to create a .CSV file to export to Excel containing only the first three lines. Example:

[CR][LF]
      Field: Microsoft.VSTS.Build.FoundIn[CR][LF]
      Name: Found In[CR][LF]
      Type: String[CR][LF]
      Use: Test project[CR][LF]
      Indexed: False[CR][LF]
      Reportable As: dimension[CR][LF]
      Synchronizes Identity Name Changes: False[CR][LF]
[CR][LF]
      Field: Microsoft.VSTS.Build.IntegrationBuild[CR][LF]
      Name: Integration Build[CR][LF]
      Type: String[CR][LF]
      Use: Test project[CR][LF]
      Indexed: False[CR][LF]
      Reportable As: dimension[CR][LF]
      Synchronizes Identity Name Changes: False[CR][LF]
[CR][LF]

(the list goes on)

Desired output:

"Microsoft.VSTS.Build.FoundIn","Found In","String"
"Microsoft.VSTS.Build.IntegrationBuild","Integration Build","String"

How can I write this in LINQ the simplest way possible?

Jeff Mercado · Accepted Answer · 2012-01-13 18:43:12Z

4

You're just breaking between "sections" on blank lines. Just go through the lines throwing everything into a separate buffer until you reach a blank line. When you do, process the items in the buffer, clear it and repeat. You can't really do this in pure LINQ simply or elegantly so don't try to force feed it into it.

var buffer = new List<string>();
foreach (var line in File.ReadLines(pathToFile))
{
    if (String.IsNullOrWhitespace(line))
    {
        ProcessSection(outputFile, buffer);
        buffer.Clear(); // or create a new one
    }
    else
    {
        buffer.Add(line);
    }
}

static void ProcessSection(StreamWriter outputFile, List<string> buffer)
{
    if (buffer.Count == 0) return;
    var contents = buffer.Take(3)
        .Select(line => String.Format("\"{0}\"", line.Substring(line.IndexOf(": ") + 2)));
    outputFile.WriteLine(String.Join(",", contents));
}

edited Jan 13, 2012 at 18:43

answered Jan 13, 2012 at 18:32

Jeff Mercado

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4 Comments

Adi Lester Over a year ago

Didn't know about File.EnumerateLines - that's pretty neat.

Jean-François Beaulieu Over a year ago

System.IO.File does not contain EnumerateLines in .NET 4.0!

Jeff Mercado Over a year ago

@JFB: Oops, sorry, wrong name. That should be ReadLines().

Jeff Mercado Over a year ago

@Lester: Warning, I botched the name of that method.

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