Reading and writing files are basic tasks needed for many Go programs. First we'll look at some examples of reading files
package main import ( "bufio" "fmt" "io" "io/ioutil" "os" ) func check(e error) { if e != nil { panic(e) } } func main() { dat, err := ioutil.ReadFile("/tmp/dat") check(err) fmt.Println(string(dat)) f, err := os.Open("/tmp/dat") check(err) b1 := make([]byte, 5) n1, err := f.Read(b1) check(err) fmt.Println("%d bytes: %s\n", n1, string(b1)) o2, err := f.Seek(6, 0) check(err) b2 := make([]byte, 2) n2, err := f.Read(b2) check(err) fmt.Println("%d bytes @ %d: %s\n", n2, o2, string(b2)) o3, err := f.Seek(6, 0) check(err) b3 := make([]byte, 2) n3, err := io.ReadAtLeast(f, b3, 2) check(err) fmt.Println("%d bytes @ %d: %s\n", n3, o3, string(b3)) _, err = f.Seek(0, 0) check(err) r4 := bufio.NewReader(f) b4, err := r4.Peek(5) check(err) fmt.Println("5 bytes: %s\n", string(b4)) f.Close() }
xjk in usa 2030 %d bytes: %s 5 xjk i %d bytes @ %d: %s 2 6 u %d bytes @ %d: %s 2 6 u 5 bytes: %s xjk i
总结 :
1 : ...
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