C# - Common String Methods Part 1

Common String Methods

Concatenation

You can concatenate strings using the + operator or the String.Concat method.

string firstName = "devesh";
string lastName = "omar";
string fullName = firstName + " " + lastName; // "devesh omar

string fullNameConcat = String.Concat(firstName, " ", lastName); // 

Interpolation

String interpolation is a more readable way to format strings.

string firstName = "devesh";
string lastName = "omar";
string fullName = $"{firstName} {lastName}"; // "devesh omar"

Format

The String.Format method provides a way to format strings.

string formatted = String.Format("Hello, {0} {1}!", firstName, lastName); // "Hello, devesh omar!"

Join

Combines multiple strings into one string with a specified separator.

string[] names = { "John", "Jane", "Doe" };
string joinedNames = String.Join(", ", names); // "John, Jane, Doe"

Searching and Substrings

We will learn about

• Contains
• IndexOf
• LastIndexOf
• Substring
• Modification-> Replace/Remove/Insert

Contains

Determines if a substring exists within a string.

string sentence = "The quick brown fox";
bool containsQuick = sentence.Contains("quick"); // true

IndexOf

Finds the zero-based index of the first occurrence of a substring.

int index = sentence.IndexOf("quick"); // 4

LastIndexOf

Finds the zero-based index of the last occurrence of a substring.

string repeatedSentence = "The quick brown fox jumps over the lazy dog. The fox is quick.";
int lastIndex = repeatedSentence.LastIndexOf("quick"); // 49

Substring

Extracts a substring from a string starting at a specified index.

string substring = sentence.Substring(4, 5); // "quick"

Modification

Replace

Replaces all occurrences of a specified substring with another substring.

string modifiedSentence = sentence.Replace("quick", "slow"); // "The slow brown fox"

Remove

Deletes a specified number of characters starting at a particular index.

string removedPart = sentence.Remove(4, 6); // "The brown fox"

Insert

Inserts a string at a specified index.

string inserted = sentence.Insert(4, "very "); // "The very quick brown fox"