Question

我正在尝试将free命令的输出分成3行。免费的一般输出是

total used free shared buff/cache available Mem: 16309236 11129884 860300 534300 4319052 4306208 Swap: 20971516 234236 20737280

但是，当我使用golang的strings.Split（）时，Split函数现在表现出预期的效果。我尝试调试它，但找不到任何东西。

请帮助。

package main

import "os/exec"
import "github.com/golang/glog"
import "fmt"
import "strings"
import "errors"

func thisWorks() {
    str_out := "hello world \n How are you \nthis is good"
    lines := strings.Split(str_out, "\n")
    fmt.Printf("lines is  \n%s\n", lines)
}

func GetFreeOutput() error {

    var errMsg string
    bytes_out, err := exec.Command("free").Output()

    // This shows that the output has 10 (newline) in it.
    fmt.Println(bytes_out)

    if err != nil {
        errMsg = "Error geting output of free command"
        glog.Fatal(errMsg)
        return errors.New(errMsg)
    }

    str_out := string(bytes_out)
    fmt.Printf("str_out is  \n%s", str_out)

    // This is not splitting the lines, it is converting the whole output to a single line.
    fmt.Println("\nLines are ", strings.Split(str_out, "\n"))

    index_of_newline := strings.Index(str_out, "\n")

    // This gives the index of "\n" as 79 on my machine, which is correct.
    fmt.Printf("\nIndex is %d", index_of_newline)

    fmt.Println("\nLine using index are ", strings.Split(str_out, string(str_out[index_of_newline])))

    return nil
}

func main() {
    err := GetFreeOutput()
    fmt.Printf("Error is %s", err)
}

Answer 1

拆分已按预期工作。问题在于您如何打印线条。

Println的第二个参数是一个切片。

 // This is not splitting the lines, it is converting the whole output to a single line.
fmt.Println("\nLines are ", strings.Split(str_out, "\n"))

根据fmt文档，切片打印为：

[elem0 elem1 ...]

请注意，元素之间用空格分隔。用\ n分割并进行打印实际上会将\ n替换为''。尝试使用以下代码来确认拆分是否按预期工作：

for i, line := range strings.Split(str_out, "\n") {
   fmt.Println(i, line)
}

无法在golang中使用“ \ n”正确分割字符串

1 个答案: