Golang itertools

I was going to do something productive today, but I got sidetracked into creating a golang library that translated python’s itertools. Its more of a thought exercise than anything else at this point, but it has a full test suite and is pretty easy to use. You can check it out on github or the documentation.

Here’s a few examples of what you can do:

// Sum of all squares who end in 3 up to 10000
summer := func (a, b interface{}) interface{} {
  return a.(int) + b.(int)
squarer := func (a interface{}) interface{} {
  return int(math.Pow(a.(float64), 2))
mod3er := func (a interface{}) interface{} {
  return a.(int) % 10 == 3
Reduce(Filter(mod3er, Map(squarer, Count(1))), summer, 0)

// Get a list of letter counts in words of a string
Map(func(a interface{}) interface{} {
  return len(a.(string))
}, New(strings.Split(someString, " ", -1)))

// Use a complicated struct as the value
type MyStruct struct {
  I int
  S string
val a, b, c MyStruct
iter := New(a, b, c)
return Filter(some_predicate, iter)

// Ordered Dict iterator
type OrderedDict struct {
  Order []string
  Dict map[string]MyType

func (od *OrderedDict) Iter() itertools.Iter {
  return Map(func(str interface{}) interface{} {
    return od[str.(string)]
  }, New(od.Order...))