Array Regex Regex Groups Regex.Matches RegexOptions.Compiled

`Regex.Matches`, quote

In C# programs, strings sometimes have quoted values—it is often useful to extract these values. This helps us parse text or code such as SQL statements.

We can use Regex for an efficient and simple way to do this. We handle quoted values with Regex. Some syntax, like escaped values, are harder to support.

Example

We match values within quotes using Regex.Matches. To use Regex.Matches, pass it a pattern—this specifies the group you are capturing. Our group here is surrounded by single quotes.

Part 1 The input string looks like an SQL query. We can see values are contained in parentheses and quotes.

Part 2 The MatchCollection is populated from the pattern specified. We use parentheses to indicate we want to capture values within quotes.

Part 3 The string array is useful if you want to copy the fields to a new array.

Part 4 The fields we captured are displayed to the console. You can see there are 5 output fields. This is our required result.

using System;
using System.Text.RegularExpressions;

// Part 1: the input string.
string line = "INSERT INTO country VALUES ('BH','BAHRAIN','Bahrain','BHR','048');";

// Part 2: match all quoted fields.
MatchCollection col = Regex.Matches(line, @"'(.*?)'");

// Part 3: copy groups to a string array.
string[] fields = new string[col.Count];
for (int i = 0; i < fields.Length; i++)
{
    fields[i] = col[i].Groups[1].Value; // (Index 1 is the first group)
}

// Part 4: display the fields.
foreach (string field in fields)
{
    Console.WriteLine(field);
}BH
BAHRAIN
Bahrain
BHR
048

Performance

Regular expressions do not result in optimal execution time. Therefore, in performance-critical situations, you will want a more complex parser.

But Often when dealing with text data, we don't require heavy performance tuning. Consider compiled Regexes.

We extracted quoted values from an input string using Regex.Matches. This style of code is sometimes useful to developers working with regular expressions.

Regex.Matches, quote

Example

Performance

`Regex.Matches`, quote