CODEWITHSUNDEEP
vb.netvisual-studiofile-iofilestream
phalanx
phalanx

Reputation: 497

How to compare strings inside a text file

I'm learning to read text files and Streamreader is the only class I know until now for that purpose. Until now I've seen this class lets me read the entire file(.ReadToEnd), line by line(.ReadLine) or character by character(.Read).

However I can't figure how to read substrings delimited by , and solve this:

( Following 4 lines are the content of textfile.txt)

COLUMN1,MAIL1,COLUMN3,COLUMN4,COLUMN5,MAIL2
".","[email protected]","1","2013-05-08 00:00:00","0","[email protected]"
".","[email protected]","1","2013-05-08 00:00:00","0","[email protected]"
".","[email protected]","1","2013-05-08 00:00:00","0","[email protected]"

If the first email address is equal to the second, do:

Numberofmatched=Numberofmatched+1

If not

Numberofunmatched=Numberofunmatched+1

Take in consideration domain name can change and email addresses have variable lenght.

Any help?

Upvotes: 0

Views: 553

Answers (1)

Tim Schmelter
Tim Schmelter

Reputation: 460158

Here's another method to read a text-file. You can use the System.IO.File class, for example File.ReadLines/File.ReadAllLines or File.ReadAllText.

Use String.Split to get a String(), one string for each column. Since the delimiter seems to be ,instead of " use String.Split(","c).

You can use following LINQ query which can increase readability:

Dim allLines = File.ReadAllLines("Path")
Dim data = From line In allLines.Skip(1) ' skip the header-line
           Where Not String.IsNullOrWhiteSpace(line)
           Let fields = line.Split(","c)
           Where fields.Length = 6
           Select fields

Dim Numberofmatched As Int32 = data.Count(Function(fields) fields(1) = fields(5))
Dim Numberofunmatched As Int32 = data.Count(Function(fields) fields(1) <> fields(5))

Note that you should use an available CSV-parser instead of reinventing the wheel since they support quoting characters and a lot of other things. One recommendable in the Visual-Basic namespace is the TextFieldParser class.

Upvotes: 1

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