如何知道Golang中任意类型的变量是否为零? [英] How to know if a variable of arbitrary type is Zero in Golang?
问题描述
因为并非所有类型都具有可比性,例如一片。所以我们不能这样做
$ b $ pre $ var $ ArbitraryType
v == reflect.Zero(reflect.TypeOf(v) ).Interface()
编辑 - 解决方案reflect.DeepEqual
var v ArbitratyType
zero:= reflect.Zero(reflect.TypeOf(v))。Interface()
转到文档关于 reflect.DeepEqual
DeepEqual测试为了深刻的平等。它在可能的情况下使用普通的==相等性,但会扫描数组,切片,地图和结构字段的元素。
解决方案 .ValueOf(v)== reflect.Zero(reflect.TypeOf(v)))
reflect.DeepEqual(reflect.ValueOf(v),reflect.Zero(reflect.TypeOf(v)))
例如各种整数0口味和未初始化 struct
s是零
可悲的是,空字符串和数组不是。和 nil
会产生一个异常。
如果您想要的话,您可以特别注意这些。
Because not all types are comparable, e.g. a slice. So we can't do this
var v ArbitraryType
v == reflect.Zero(reflect.TypeOf(v)).Interface()
Edit - Solution reflect.DeepEqual
var v ArbitratyType
zero := reflect.Zero(reflect.TypeOf(v)).Interface()
isZero := reflect.DeepEqual(v, zero)
Go documentation about reflect.DeepEqual
DeepEqual tests for deep equality. It uses normal == equality where possible but will scan elements of arrays, slices, maps, and fields of structs.
解决方案 Both of the following give me reasonable results (probably because they're the same?)
reflect.ValueOf(v) == reflect.Zero(reflect.TypeOf(v)))
reflect.DeepEqual(reflect.ValueOf(v), reflect.Zero(reflect.TypeOf(v)))
e.g. various integer 0 flavours and uninitialized struct
s are "zero"
Sadly, empty strings and arrays are not. and nil
gives an exception.
You could special case these if you wanted.
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