格式化错误.新 [英] Formatted errors.New

问题描述

我想实现一个errors.New版本，该版本接受与fmt.Sprintf相同的参数.为此，我编写了以下函数:

I would like to implement a version of errors.New that accepts the same parameters as fmt.Sprintf To do so I wrote the following function:

func NewError(format string, a ...interface{}) error {
    return errors.New(fmt.Sprintf(format, a))
}

但是，a成为NewError()内部的单个数组参数，从而导致Sprintf()仅填写格式字符串中的单个参数.如何强制将a解释为可变数量的参数?

However, a becomes a single array parameter inside NewError() thereby causing Sprintf() to fill out just a single parameter in the format string. How can I force a to be interpreted as a variable number of arguments?

推荐答案

fmt.Errorf 已经做了什么您正在尝试做.查看其来源，您可以查看出了什么问题:

fmt.Errorf already does what you are trying to do. Looking at its source, you can see what went wrong:

// Errorf formats according to a format specifier and returns the string
// as a value that satisfies error.
func Errorf(format string, a ...interface{}) error {
        return errors.New(Sprintf(format, a...))
}

请注意，您的代码在a之后缺少....从规范:

Note your code is missing the ... after a. From the spec:

将参数传递给...参数

如果最终参数可分配给切片类型[]T，则在参数后跟...的情况下，可以将其不变地作为...T参数的值传递.在这种情况下，不会创建新的切片.

Passing arguments to ... parameters

If the final argument is assignable to a slice type []T, it may be passed unchanged as the value for a ...T parameter if the argument is followed by .... In this case no new slice is created.

给出切片s并调用

s := []string{"James", "Jasmine"}
Greeting("goodbye:", s...)

在Greeting内，其值与s相同，且具有相同的基础数组.

within Greeting, who will have the same value as s with the same underlying array.

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