go_junior_to_mid

This repo，it includes almost all basic usages and knowledge for junior. And it also includes some knowledge for mid.

If you are not a junior, please go to https://github.com/ramseyjiang/go_mid_to_senior, almost the whole repo has unittests.

All codes in this repo, after you clone, if you want to run in your local,

1. Please change all pkg names to main.
2. After step 1, please open your terminal, go the file folder, and execute "go run filename.go"

Golang has 8 differences from other Object-Oriented languages.

1. The first thing is you should take care of types in Go.

2. The biggest difference is that GO does not provide Classes, it has Structs. They have basically stripped down classes, and bundles of data with methods. A struct can have many attributes, and you can attach methods that any instances of that struct can call. Methods can also be public or private, as well as attributes using both UpperCamelCase for public and lowerCamelCase for privates. The key difference between GO structs and classes is that it does not allow inheritance. They do not have inherent constructors as classes do and that interfaces are implemented implicitly, which means that you do not have to specify that a class implements an interface, if it implements the methods of the interface, it implies it implements the interface as well.

3. Golang does not quite really support Inheritance, you could use inheritance but what you would be using deep down is composition, which is the recommended way. Composition is basically using a class that uses some other classes, like assembling the different components of a PC and making them work together. Composition in Go is normally implemented using dependency injection, in which you pass the dependencies or components to a class instead of letting the class instantiate it itself. This can make the code much cleaner since you can track the dependencies to a common source instead of having them all over the place. It also helps you to build unit tests since it is easier to mock the dependencies.

4. Go is missing many of the main data structures common in other languages like built-in trees and sets. First, you’ve got arrays and slices that behave in a very similar way with the main difference being that arrays are immutable. Second, you have structs. Finally, there’s the map, the map is pretty much like any other map or dictionary in any other language, you have a key-value data structure.

5. Error handling is also really different in Go. First, Go lacks one key component in most programming languages: the try-catch statement. So Go does not let you wrap your entire code into a single try-catch to screw up as much as you’d like. If you think that a certain part of your code is risky or error-prone, you should handle that part individually with its one conditions and proper response.

So the way that Go does this is by having two responses on its functions, normally the standard says that you should return an error alongside your response and wherever you invoke that function, you’d either get that error and validate it with an if statement, or you’ll just ignore it using a blank identifier (_) to move on.

6. In Go, it only has double quotes, it does not have a single quote.

7. In Go, if you want to use ++i, sorry, it will have an error. Because it does not exist, you only can use i++.

8. In Go, defining const is different from Java, but it is similar to PHP. When you define a const, if you base on Java, your way, such as “GO_CONST” should not use. In Go, it defines const using this way “GoConst”, the first character capital or not depending on the variable scope.

If you want to learn more go to the official rules, please check https://go.dev/doc/effective_go by yourself.