Introduction Go
Table of Contents
1. Basic commands
1.1. How do we run the code in our project?
1.1.1. go run
- It compiles the file and execute it
- go run main.go
1.1.2. go build
- It generates an executable file, just that, it does not execute it.
1.1.3. go fmt
- It is go format (fmt), it is useful to format all the code in each file in the current directory.
1.1.4. go install / go get
- go install compiles and installs a package, go get downloads the raw source code of someone else’s package.
1.1.5. go test
- Runs any tests associated with the current project
1.2. What does ’package main’ mean?
Files in the same package can freely call functions defined in other files.
1.2.1. Executable package
- the word main is a keyword, we use it only when we are makin a package that we want to spit out some reasonable file.
- package main:
- defines a package that can be compiled and then executed, must have a func called ’main’
- package main:
1.2.2. Reusable package
- Package abcxyz:
- defines a package that can be used as a dependency
1.3. What does ’import “ftm”’ mean?
ftm contains input and output functions, it is like System.Out.println.
1.4. What is that func thing?
It is a short of function, it is a function like any other programming language.
1.5. How is the main.go file organized?
| package main | package declaration |
| import “fmt” | import other packages that we need |
| func main(){ ftm.Println(“hi there”)} | Declare functions, tell Go to do things |
2. Variables
2.1. Declare a variable
Go is a typed programming language, variables must first be initialized with the ’:=’ operator or the ’var variableName type’ syntax, so there are a few ways to declare a variable:
- var card string = “Ace of spades”
- card := “Ace of spades”
- :=
it is only used to declare or inicialize a variable, after we can use = to assigned another value, take into account that the type of value once is declared can not be changed, in this case always is gonna be string.
- :=
3. Data structures
3.1. slices
They are dinamyc data structures.
3.2. Arrays
They are fixed data structures.
4. Iterate
for i, card := range cards { fmt.Println(i, card) }