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modified: eBook/18.3.md modified: eBook/18.4.md modified: eBook/18.5.md modified: eBook/18.6.md modified: eBook/18.7.md modified: eBook/18.8.md modified: eBook/18.9.md
52 lines
1.2 KiB
Markdown
52 lines
1.2 KiB
Markdown
# 18.7 文件
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（1）如何打开一个文件并读取：
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```go
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file, err := os.Open("input.dat")
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if err != nil {
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fmt.Printf("An error occurred on opening the inputfile\n" +
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"Does the file exist?\n" +
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"Have you got acces to it?\n")
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return
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}
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defer file.Close()
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iReader := bufio.NewReader(file)
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for {
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str, err := iReader.ReadString('\n')
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if err != nil {
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return // error or EOF
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}
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fmt.Printf("The input was: %s", str)
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}
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```
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（2）如何通过切片读写文件：
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```go
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func cat(f *file.File) {
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const NBUF = 512
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var buf [NBUF]byte
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for {
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switch nr, er := f.Read(buf[:]); true {
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case nr < 0:
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fmt.Fprintf(os.Stderr, "cat: error reading from %s: %s\n",
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f.String(), er.String())
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os.Exit(1)
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case nr == 0: // EOF
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return
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case nr > 0:
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if nw, ew := file.Stdout.Write(buf[0:nr]); nw != nr {
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fmt.Fprintf(os.Stderr, "cat: error writing from %s: %s\n",
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f.String(), ew.String())
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}
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}
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}
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}
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```
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## 链接
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- [目录](directory.md)
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- 上一节：[函数](18.6.md)
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- 下一节：[协程（goroutine）与通道（channel）](18.8.md) |