Introduction
The article demonstrates the IndexOfAny() method to locate the initial occurrence of any string from a chosen array. Additionally, you utilize LastIndexOf() to pinpoint the last occurrence of a string within another string.
Learning Objectives
Learn to use LastIndexOf() method
Learn to use IndexOfAny() method
Prerequisites for Developers
Basic familiarity with string helper methods
Basic understanding of while iteration statements
Proficiency in using Visual Studio or Visual Studio Code for C# code development, building, and execution
Getting Started
LastIndexOf Method
To enhance the complexity of the “message” variable by incorporating numerous sets of parentheses, followed by coding to extract the content enclosed within the last set of parentheses.
To begin, create a static class file called “StringMethodsPart2.cs” within the console application. Insert the provided code snippet into this file.
{
/// <summary>
/// Outputs
/// Searching THIS message: Help (find) the {opening symbols}
/// Found WITHOUT using startPosition: (find) the { opening symbols }
/// </summary>
public static void IndexOfAnyMethod()
{
string message = “Help (find) the {opening symbols}”;
Console.WriteLine($”Searching THIS Message: {message}“);
char[] openSymbols = [‘[‘, ‘{‘, ‘(‘];
int openingPosition = message.IndexOfAny(openSymbols);
Console.WriteLine($”Found WITHOUT using startPosition: {message.Substring(openingPosition)}“);
}
}
Execute the code from the main method as follows
StringMethodsPart2.IndexOfAnyMethod();
#endregion
Console Output
IndexOfAny Method
Utilize .IndexOfAny() to retrieve the index of the initial symbol from the openSymbols array that is present in the message string.
To do that add another method into the same static class as shown below
/// Outputs
/// set of parentheses
/// </summary>
public static void LastIndexOfMethod() {
string message = “(What if) I am (only interested) in the last (set of parentheses)?”;
int openingPosition = message.LastIndexOf(‘(‘);
openingPosition += 1;
int closingPosition = message.LastIndexOf(‘)’);
int length = closingPosition – openingPosition;
Console.WriteLine(message.Substring(openingPosition, length));
}
Execute the code from the main method as follows
StringMethodsPart2.LastIndexOfMethod();
#endregion
Console Output
Found WITHOUT using startPosition: (find) the {opening symbols}
Complete Code on GitHub
GitHub — ssukhpinder/30DayChallenge.Net
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