Searching for elements in arrays in C# .NET

The Array class has a number of useful static methods. A group of them is used for searching purposes. The method names are generally quite descriptive. Here are some them with comments in the code:

string[] bands = new string[6] { "Queen", "ACDC", "Metallica", "Genesis", "INXS", "Motörhead" };

//find the first entry in the array which starts with Q, finds "Queen"
string firstBandStartingWithQ = Array.Find<string>(bands, s => s.StartsWith("Q"));
//finds last entry start with M, finds Motörhead
string lastBandStartingWithM = Array.FindLast<string>(bands, s => s.StartsWith("M"));
//finds Metallica and Motörhead and puts them in an array
string[] allWithM = Array.FindAll<string>(bands, s => s.StartsWith("M"));
//index will be 0 as Queen is the first item in the array
int queenIndex = Array.FindIndex<string>(bands, s => s == "Queen");
//yields true as ACDC figures in the array
bool acdIsThere = Array.Exists<string>(bands, s => s == "ACDC");	

View all various C# language feature related posts here.

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How to pass any number of parameters into a method in C# .NET

You must have come across built-in methods in .NET where you can send any number of arguments into a method. E.g. string.Format has an overload where you can pass in a format string and then an array with the “params” modifier.

There’s nothing stopping you from using the same keyword to write a similar method, here’s an example:

public void MethodWithParams(int toBeMultiplied, params int[] multipliers)
{
	foreach (int m in multipliers)
	{ 
		Console.WriteLine(string.Format("{0} x {1} = {2}", toBeMultiplied, m, toBeMultiplied * m));
	}
}

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Searching for elements in arrays in C# .NET

The Array class has a number of useful static methods. A group of them is used for searching purposes. The method names are generally quite descriptive. Here are some them with comments in the code:

string[] bands = new string[6] { "Queen", "ACDC", "Metallica", "Genesis", "INXS", "Motörhead" };

//find the first entry in the array which starts with Q, finds "Queen"
string firstBandStartingWithQ = Array.Find<string>(bands, s => s.StartsWith("Q"));
//finds last entry start with M, finds Motörhead
string lastBandStartingWithM = Array.FindLast<string>(bands, s => s.StartsWith("M"));
//finds Metallica and Motörhead and puts them in an array
string[] allWithM = Array.FindAll<string>(bands, s => s.StartsWith("M"));
//index will be 0 as Queen is the first item in the array
int queenIndex = Array.FindIndex<string>(bands, s => s == "Queen");
//yields true as ACDC figures in the array
bool acdIsThere = Array.Exists<string>(bands, s => s == "ACDC");	

View all various C# language feature related posts here.

Create a List using Arrays.asList in Java 8

Java 8 has a number of new methods on Collections. One such utility method is the static asList method with which you can quickly create a List of T.

Here’s how it works for a List of integers:

List<Integer> asList = Arrays.asList(1,2,3,4);

…and for a List of strings:

List<String> asList = Arrays.asList("hello", "my", "dear", "world");

View all posts related to Java here.

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