在高隆赶上恐慌 [英] Catching panics in Golang

问题描述

使用以下代码，如果没有给出文件参数，则会抛出第9行的紧急情况 panic：runtime error：index out of range as expected。

With the following code, if no file argument is given, a panic is thrown for line 9 panic: runtime error: index out of range as expected.

我如何抓住这个恐慌，直接传递给它时处理它（ os.Args [1] ）导致恐慌？很像PHP中的try / catch或者在Python中尝试/除外。

How can I 'catch' this panic and handle it when directly when passing something to it (os.Args[1]) that causes the panic? Much like try/catch in PHP or try/except in Python.

我在StackOverflow上搜索了一下，但是我没有找到任何答案。

I've had a search here on StackOverflow but I've not found anything that answers this as such.

package main

import (
    "fmt"
    "os"
)

func main() {
    file, err := os.Open(os.Args[1])
    if err != nil {
        fmt.Println("Could not open file")
    }
    fmt.Printf("%s", file)
}

推荐答案

Go不是python，你应该在使用它之前正确检查args：

Go is not python, you should properly check for args before you use it:

func main() {
    if len(os.Args) != 2 {
         fmt.Printf("usage: %s [filename]\n", os.Args[0])
         os.Exit(1)
    }
    file, err := os.Open(os.Args[1])
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s", file)
}

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