C# `String.Equals()`: Mastering String Comparison Techniques

Learn how to effectively compare strings in C# using the `String.Equals()` method. This tutorial explores its various overloads, demonstrating how to perform case-sensitive and case-insensitive comparisons, handle different cultures, and choose the optimal approach for your string manipulation tasks.

Using C#'s `String.Equals()` Method for String Comparison

The C# `String.Equals()` method compares two strings to check if they have the same value. It's a fundamental method for string manipulation and is crucial for tasks involving string comparisons and equality checks.

`String.Equals()` Method Overloads

The `Equals()` method is overloaded, providing several ways to compare strings:

  • public bool Equals(string value): Compares the current string instance with a specified string.
  • public static bool Equals(string a, string b): Compares two strings.
  • public override bool Equals(object obj): Compares the current string with another object (the object must be a string).
  • public static bool Equals(string a, string b, StringComparison comparisonType): Compares two strings with a specified comparison type (ordinal, ignore case, culture-sensitive, etc.).
  • public bool Equals(string value, StringComparison comparisonType): Compares the current string instance with specified string and comparison type.

Parameters

The parameters vary depending on the overload. They generally include one or two strings to compare and an optional `StringComparison` value to control the comparison (case sensitivity, culture-specific rules, etc.).

Return Value

The `Equals()` method returns `true` if the strings are equal according to the specified comparison; otherwise, `false`.

Example: Comparing Strings


string str1 = "hello";
string str2 = "Hello";
bool isEqual = str1.Equals(str2, StringComparison.OrdinalIgnoreCase); // true
Console.WriteLine(isEqual);

This example uses the overload that takes a `StringComparison` to perform a case-insensitive comparison. Note that without specifying a `StringComparison`, the comparison is culture-sensitive.