Generics in Go:
Generics let us use type parameters in functions and data structures. This boosts code flexibility and reusability without losing type safety. Essentially, you can create a function that takes an argument of any type, denoted as the variable T.




Type parameters, seen above before the ordinary parameters with square brackets, allow for flexible data types. In many cases, you might not want to allow the "any" type and instead restrict certain types that can be used. You can impose specific type constraints for more control. For instance, the pre defined "comparable" constraint ensures values can be compared using == and != operators.




For constaints that are more complex, such as ensuring a type supports ordering (<, <=, >=, >), the constants package provides predefined constraints.You can apply custom constraints to ensuring types adhere to specific interfaces. For instance, to create a box that stores items with the "Drive" method, you'd require them to implement the "vehicle" interface.




You can also define methods on these generic types:




Union Types:
A union type lets a type parameter be one of multiple possible types, separated by the "|" symbol.




In the function above, "T" can either be an int, string, or a float64. The same works for a generic data structure:




Type Approximation:
Using union for all base types won't cover derived types because it's not in our union. The "~" symbol indicates a match for the given type and its derived types. For instance, ~string would match both string and any type derived from it.