Go Language Tour: Package

Each Go program is made up of some packages.

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The program main starts execution from the package.

package mainimport (    "fmt"    "math/rand")func main() {    fmt.Println("My favorite number is", rand.Intn(10))}

In this program, import two packages via import, fmt and math/rand (package path).

By convention, the package name is the same as the last part of the package path. For example, math/rand the source files in the package package rand begin with a statement.

Import statement

Go introduces the package through the import statement and is used in the code.

importThere are two different ways to write a statement, and the above example is one of them- bulk import ; the second is divided into multiple statements:

import "fmt"import "math"

Although there is no real difference between the two styles, it is recommended to use bulk notation , which is the best style .

Name Export

In the Go language, names beginning with uppercase letters are exported ( exported ). An example Pizza is an export name, which math is also in the package Pi .

package main import (     "fmt"     "math" ) func main() {     fmt.Println(math.Pi) }

Instead, pizza and pi because it is not capitalized, it is not exported.

After a package is imported, it can only be referenced to the exported name. Any other non-exported name outside the package is not accessible (not visible).

Next

In the next section, let's take a look at the Go language function.

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