Summary of the use of various newreaders and newbuffers in Go

func main() {
    var byteArr []byte
    buf := (byteArr)
    ([]byte("Good today"))
 
    (())
}

package main
 
import (
    "bytes"
    "fmt"
)
 
func main() {
    data := []byte("Lu Duosin's thoughts")
    reader := (data)
 
    // Read the entire byte array    buf := make([]byte, len(data))
    _, err := (buf)
    if err != nil {
        ("Read failed:", err)
    }
    ("Bytes read:", buf)
 
    // Read part of the byte slice    part := make([]byte, 3)
    _, err = (part)
    if err != nil {
        ("Read failed:", err)
    }
    ("Bytes read:", part)
 
    // Find and read a character in a byte slice    offset, err := (6, 0)
    if err != nil {
        ("Seek failed:", err)
    }
    ch, size, err := ()
    if err != nil {
        ("ReadRune failed:", err)
    }
    ("Read %c with size %d at offset %d\n", ch, size, offset)
}

    r := ("abcdefghijklmn")
    (())   // Output 14 Initially, the unread length is equal to the string length    var buf []byte
    buf = make([]byte, 5)
    readLen, err := (buf)
    ("Length read:", readLen) //The length read is 5    if err != nil {
        ("mistake:", err)
    }
    (buf)            //adcde
    (())        //9 5 reads, the remaining unread is 14-5    (())       //14 length of string

package main
import (
    "fmt"
    "io"
    "os"
)
func main() {
    ("Hike.com()")
    fileName := "C:/"
    file, err := (fileName)
    if err != nil{
        ("Read file err, err =", err)
        return
    }
    defer ()
    var chunk []byte
    buf := make([]byte, 1024)
    for{
        n, err := (buf)
        if err != nil && err != {
            ("read buf fail", err)
            return
        }
        //Instructions the end of reading        if n == 0 {
            break
        }
        //Read to the final buffer        chunk = append(chunk, buf[:n]...)
    }
    ("File Content =", string(chunk))
}

package main
import (
    "bufio"
    "fmt"
    "io/ioutil"
    "os"
)
func main() {
    ("Hike.com()")
    var(
        fileName = "C:/"
        content = "Hello HaiCoder"
        file *
        err error
    )
    //Use append mode to open the file    file, err = (fileName, os.O_APPEND, 0666)
    if err != nil{
        ("Open file err =", err)
        return
    }
    defer ()
    writer := (file)
    //Write to file    n, err := ([]byte(content))
    if err != nil{
        ("Write file err =", err)
        return
    }
    ("Write file success, n =", n)
    ()
    //Read the file    fileContent, err := (fileName)
    if err != nil{
        ("Read file err =", err)
        return
    }
    ("Read file success =", string(fileContent))
}