• Since Pattern matching has been added in C# 7.0, it has evolved from strength to strength in every version of the language since.
• is and switch are the 2 keywords that enable to apply a pattern along with relational <, >, <=, >= and logical not, and, or operators.
• It allows to build powerful yet succint logic in an elegant way.
• From personal experience, it is easy to get carried away and pack several scenarios in a small space however adopting a TDD approach covering each scenario will guard against regression and make it easy to control changes.

Introduced in C# 7.0

Pattern	Description
Declaration	Defines an expression that gets evaluated at runtime and the expression result gets assigned to a variable if the matching criteria is true
Constant	An expression gets evaluated and compared a constant
var	An expression gets evaluated and result is assigned to a declared variable

Introduced in C# 8.0

Pattern	Description
Property	Evaluates an expression and checks if the properties and fields match nested patterns
Positional	Called as such because the position of the property in a deconstructed result matters when an expression is evaluation. Can also do tuple comparison.
Discard	Uses the _ variable, usually as a default handling, null check or where the result of the evaluated expression is not used ultimately

Introduced in C# 9.0

Pattern	Description
Type	Evaluate an expression and check the runtime type
Relational	Use relational operators in a switch statement to compare with a specified constant
Logical	Evaluates an expression and use logical operators to compare with one or more patterns