英文:
Variable definition is not defined
问题
我已经搜索了Google并看到了一些示例，但是还是不太明白。我刚开始学习Go语言，所以希望有人能为我解释一下。我有以下的代码：
var configFile string
var keyLength int
var outKey string
var outconfig string
for index, item := range args {
if strings.ToLower(item) == "-config" {
configFile = args[index + 1]
}else if strings.ToLower(item) == "-keylength" {
keyLength, _ = strconv.Atoi(args[index + 1])
}else if strings.ToLower(item) == "-outkey" {
outKey = args[index + 1]
}else if strings.ToLower(item) == "-outconfig" {
outconfig = args[index + 1]
}
}
但是在定义所有变量的地方，我得到了一个错误，错误信息是"configFile declared but not used"。如果我能得到一些建议，帮助我更好地理解这个问题。
英文:
I've searched Google and saw some samples, but it's just not clicking. I'm new to Go, so I hope someone can clarify this for me. I have the following code:
var configFile string
var keyLength int
var outKey string
var outconfig string
for index, item := range args {
if strings.ToLower(item) == "-config" {
configFile = args[index + 1]
}else if strings.ToLower(item) == "-keylength" {
keyLength, _ = strconv.Atoi(args[index + 1])
}else if strings.ToLower(item) == "-outkey" {
outKey = args[index + 1]
}else if strings.ToLower(item) == "-outconfig" {
outconfig = args[index + 1]
}
}
But I'm getting an error for all the variables where it's being defined with the following error "configFile declared but not used". If I can get some advice to help me better understand this problem
答案1
得分: 0
你给变量赋值，但之后从未使用过它们。这就是为什么 Go 抛出错误。
看看这个例子：
package main
func f() {
var unassignedVar string
var unusedVar = "I am not read"
var usedVar = "I am read"
print(usedVar)
}
对于前两个变量，Go 会抛出错误：unassignedVar 甚至没有被赋值，unusedVar 被赋了一个值但之后没有使用。usedVar 被赋了一个值并在后面使用了。
在 Go Playground 上查看示例：https://go.dev/play/p/72lRGyxDn4Y。
英文:
You assign values to the variables, but never use them after. That's why Go throws an error.
See this example:
package main
func f() {
var unassignedVar string
var unusedVar = "I am not read"
var usedVar = "I am read"
print(usedVar)
}
For the first two variables, Go will throw an error: unassignedVar is not even assigned a value, unusedVar is assigned a value but not used afterwards. usedVar is both assigned a value and used later on.
See the example on the Go Playground.
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