Question

What are Regular expressions? Search a string using regular expressions?

Answer 1

Regular expression is a template to match a set of input. The pattern can consist of operators, constructs or character literals. Regex is used for string parsing and replacing the character string.

For Example:

* matches the preceding character zero or more times. So, a*b regex is equivalent to b, ab, aab, aaab and so on.

Searching a string using Regex

1	static void Main(string[] args)

2

{

3	string[] languages = { "C#", "Python", "Java" };

4	foreach(string s in languages)

5

{

6	if(System.Text.RegularExpressions.Regex.IsMatch(s,"Python"))

7

{

8	Console.WriteLine("Match found");

9

}

10

}

11

}

The above example searches for “Python” against the set of inputs from the languages array.