How Can I Check for Zero Values of Arbitrary Types in Go?

Checking for Zero Value of Arbitrary Types in Golang

One of the common tasks in programming involves determining if a variable is initialized or has its default value. However, this can be challenging in Golang due to the lack of a universal zero value across all types.

Challenge of Comparing

The conventional approach of comparing a variable to the reflection's Zero() value doesn't always work because not all types are comparable. For example, slices are not comparable, making it impossible to use the following code:

var v ArbitraryType
if v == reflect.Zero(reflect.TypeOf(v)).Interface() {
    // v is zero
}

Solution with Value.IsZero()

Fortunately, Go 1.13 introduced the Value.IsZero() method in the reflect package. This method provides a solution to check if a variable of arbitrary type is zero. The syntax is:

reflect.ValueOf(v).IsZero()

This method works not only for basic types but also for:

• Chan
• Func
• Array
• Interface
• Map
• Ptr
• Slice
• UnsafePointer
• Struct

Usage Example

To determine if a variable v of an arbitrary type is zero:

if reflect.ValueOf(v).IsZero() {
    // v is zero
}

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