Predefined identifiers in Go language

Predefined identifiers of the Go language are special keywords with specific meanings and cannot be used for other purposes. Built-in types: bool, string, byte, rune, int, uint, float, etc. Constants: true, false, iota. Functions: len (length), cap (capacity), new (allocate memory), make (create a collection), append (append elements), copy (copy elements). Others: defer (delayed execution function), go (start goroutine), package (define package), import (import package).

Predefined Identifiers in Go Language: Getting Started

Predefined identifiers are special keys reserved in Go language words, they have a specific meaning and cannot be used for other purposes. Understanding and correctly using these identifiers is crucial to writing effective Go code.

Built-in type

• bool: Represents Boolean value (true/false)
• string: Represents a string
• byte: Represents a single byte value
• rune: Represents a Unicode code point
• int, int8, int16, int32, int64: represents signed integer, the size increases in order
• uint, uint8, uint16, uint32, uint64: represents an unsigned integer, the size increases in order
• float32, float64: Represents floating point numbers, and the precision increases in order

Constant

• true, false: Boolean constant
• iota: Incremental constant generator

Function

• len: Returns the length of the collection (for example, the length of a string or array)
• cap : Returns the capacity of the slice
• new : Allocates memory and returns a pointer to it
• make : Creates and returns a collection (for example, map or slice)
• append: Append elements to slice or map
• copy: Copy elements

Others

• defer: Execute the delay function before the function returns
• go: Start a goroutine (concurrent execution Function)
• package: Define a Go package
• import: Import other packages

Practical case

The following is a Go code snippet that demonstrates how to use predefined identifiers:

package main

import "fmt"

const (
    name = "John Doe"
    age = 30
)

func main() {
    length := len(name)
    fmt.Println("Name:", name, "Length:", length)

    numbers := []int{1, 2, 3, 4, 5}
    fmt.Println("Numbers:", numbers, "Length:", len(numbers))

    defer fmt.Println("Done!")
    fmt.Println("Age:", age, "Type:", reflect.TypeOf(age))

    go func() { fmt.Println("This is a goroutine.") }()
}

In this example, we used the following predefined identifiers:

• const: Define a constant
• len: Get the length of a string or array
• defer : Delayed execution of functions
• go: Start a goroutine

Understanding and correct use of predefined identifiers is essential for writing clear, concise, and efficient Go code important.

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