Learn About String In C#

Introduction

In C#, we have a primitive type specifically for string. You don’t have to use char array as in C++. We also have a class “String” in C# for extra string operations.

Note
String is a primitive type and String is a class. For better understanding, know that String class is bold.

You can create a string in any of the below methods:

string firstName;
firstName = null;
firstName = string.Empty;
firstName = "";
firstName = "Hello";
char[] letters = { 'C', ' ', 'S', 'h', 'a', 'r', 'p' };
string objString = new string(letters);

Concatenation

string lastName = "World";
string output = firstName + lastName;
Console.WriteLine("Output = " + output);
output = firstName + " " + lastName;
Console.WriteLine("Output = " + output);

Join String Array

Syntax : String.Join(delimiter, string_Array);

string[] joinArray = { "String", "Join", "Done", "Successfully" };
string joinOutput = String.Join("-", joinArray);
Console.WriteLine("Output = " + joinOutput);
string joinOutput2 = String.Join(" ", joinArray);
Console.WriteLine("Output = " + joinOutput2);
string joinOutput3 = String.Join(" ", joinArray) + ".";
Console.WriteLine("Output = " + joinOutput3);

Split String Data into Array

string splitableContent = "Hello from Karthi";
string[] splitContent = splitableContent.Split(' ');
foreach (string word in splitContent)
{
Console.WriteLine(word);
}

Length & Count

string abc = "Hello";
char[] lettersArray = { 'C', ' ', 'S', 'h', 'a', 'r', 'p' };
Console.WriteLine(abc.Length);
Console.WriteLine(lettersArray.Count());

Length is a property of string & Array.

Output

Length = 5

Count = 7

Format String Value

Format method of String Class is used to format string value based on your needs.

DateTime todayDate = DateTime.Now;
string formattedVal = String.Format("Time: {0:t} and Date : {0:D}", todayDate);
Console.WriteLine("Format String = " + formattedVal);

Copy String

string a = "Hai";
string b = string.Copy(a);
Console.WriteLine("A = " + a);
Console.WriteLine("B = " + b);

Compare String

Compare method of string compares two string and returns the 0, 1 or -1.

If both are the same, it returns 0.

If the first one is bigger, it returns 1.

If the second one is bigger, it returns -1.

Syntax

int Compare (string a, string b);
int Compare(string a, string b, true);

The third parameter is used and set to true when you want to compare two strings ignoring case.

//Compare
string sa1 = "Hello";
string sa2 = "hello";
Console.WriteLine("Compare = " + string.Compare(sa1, sa2));
Console.WriteLine("Compare = " + string.Compare(sa1, sa2, true));

String Equality

Equals method checks whether two strings are the same and returns true or false.

string se1 = "hello";
string se2 = "hello";
Console.WriteLine("Equals = " + string.Equals(se1, se2));
Console.WriteLine("Equals 2 = " + se1.Equals(se2));

Contains & EndsWith

Contains method checks whether the string contains the specified string.

EndsWith method checks whether the string ends with the specified string.

string stringObj = "this is a big sentence with number one";
Console.WriteLine("Contains 'one' = " + stringObj.Contains("one"));
Console.WriteLine("EndsWith 'one' = " + stringObj.EndsWith("one"));