Pattern Matching in C#

The article presents pattern matching in C# as a modern way to make decisions based on type, value, ranges, properties, or multiple inputs at once. It shows how switch, is, and switch expressions can replace longer nested if chains with simpler code.

Reading notes

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• Type patterns check whether an expression is non-null and whether it matches a specified type, with examples using Animal, Cat, and Dog.
• Constant patterns compare a value against fixed strings such as “Meow” and “Bark”.
• Relational patterns use operators like <, >, <=, and >= to return different messages for numeric ranges.
• Logical patterns combine and, or, and not with other patterns, including null checks and age ranges.
• Property patterns match a non-null object by checking named properties such as Name, Description, and Cloned.
• Positional patterns compare multiple values together by turning method arguments into a tuple.
• Var patterns store a value temporarily from an expression and then test the stored result against other conditions.