Three new books, Go Optimizations 101, Go Details & Tips 101 and Go Generics 101 are published now. It is most cost-effective to buy all of them through this book bundle in the Leanpub book store.

reflect 2

What does the following program print?

package main

import "reflect"

type T struct{
  A int
  b int
}

func (T) M() {}
func (T) m() {}

func main() {
	v := reflect.ValueOf(T{})
	println(v.NumField(), v.NumMethod())
}

Choices:

Answer: 2 1

Run it on Go play.

Key point:

the reflect.Value.NumMethod method only counts exported methods for non-interface types/values.
the reflect.Value.NumField method counts both exported and unexported fields.

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Articles in this book:

slice: 1, 2, 3
map: 1
channel: 1
loop: 1, 2, 3, 4
switch: 1
defer: 1, 2
panic/recover: 1, 2
reflect: 1, 2
const: 1, 2, 3, 4
operator: 1, 2, 3
function call: 1
scope: 1, 2
nil: 1
embedding: 1

(more are coming ...)