Regex.Matches, quote

Regex.Matches can handle quoted data. We parse a String containing fields inside quotes in VB.NET—special care must be taken with the expression pattern.

When parsing some files, we may have to deal with quoted values. We show an example of parsing a textual list. Some clever code to detect the quotes is helpful.

Required input and output

Consider this example string that contains the word "Bahrain" in single quotes. We want to extract the terms, eliminating the surrounding characters.

Input:
('BH','BAHRAIN','Bahrain','BHR','048')
BH
BAHRAIN
Bahrain
BHR
048

Example

We first import System.Text.RegularExpressions. This program matches all the quoted values within the example value string.

Imports System.Text.RegularExpressions

Module Module1
    Sub Main()
        Dim value As String = "('BH','BAHRAIN','Bahrain','BHR','048')"

        ' Step 1: match data between single quotes hesitantly.
        Dim result As MatchCollection = Regex.Matches(value, "'(.*?)'")

        ' Step 2: loop through Matches.
        For Each m As Match In result

            ' Step 3: access first Group and its value.
            Dim group = m.Groups(1)
            Console.WriteLine(group.Value)

        Next
    End Sub
End Module
BH
BAHRAIN
Bahrain
BHR
048

Some notes

There are alternative methods you can use to accomplish this same task. A For-loop that appends the substrings to a List could work, or Regex.Split could be called.

With a Regex, we can extract substrings from inside certain characters such as quotes. The Regex pattern can be changed for each program's needs as well.