Go is not an easy language(arp242.net)

  arr2 := []int{}
  for i := range arr1 {
    if arr1[i] > 9 {
      arr2 = append(arr2, arr1[i] * 2)
    }
  }

  var arr2 = arr1.Where(x => x > 9).Select(x => x*2);
  var arr2 = from x in arr1 where x > 9 select x*2;
  arr2 = [x * 2 for x in arr1 where x > 9]
  (setf arr2 (loop for x across arr1 when (> x 9) collect (* x 2)))

  array[i] = 9
  *pointer = 9
  array[i].fieldName = 9
  (*pointer).fieldName = 9
  structValue.fieldName = 9  
  pointer->fieldName = 9 // Go equivalent: pointer.fieldName = 9

  // you can also create a pointer to any of these lvalues
  // in either language with &

  struct test {
    int a;
  } global;

  struct test* foo() {
    return &global;
  }

  int main (int argc, char**argv) {
    printf("%d", global.a); //wil print 0

    foo()->a = 9;
    //or (*(foo())).a = 9;

    printf("%d", global.a); //will print 9
  }

  func (x Outer) Frobnicate(val int) {
    x.inner.Frobnicate(val)
  }

  type Outer struct {
    Inner
  }

  func process(i Inner) { ... }

  var x Outer
  process(x)       // ERROR: type mismatch
  process(x.Inner) // OK

  type Avariant struct {
    a int
  }
  type Bvariant struct {
    b string
  }
  type SumChoice int
  const (
    SumA SumChoice = 0
    SumB SumChoice = 1
  )
  type Sum struct {
    type SumChoice
    A *Avariant
    B *Bvariant
  }

  sumA := Sum{choice: SumA, A: &{a: 7} }
  sumB := Sum{choice: SumB, B: &{b: "abc"} }

  func foo (x Sum) {
    switch(x.choice) {
      case SumA: {
        fmt.Printf("Value is %d", x.A.a)
      }
      case SumB: {        
        fmt.Printf("Value is \"%s\"", x.B.b)
      }
    }
  }

  func foo (x interface{}) {
    switch actual := x.(type) {
      case AVariant: {
        fmt.Printf("Value is %d", actual.a)
      }
      case BVariant: {        
        fmt.Printf("Value is \"%s\"", actual.b)
      }
    }
  }

    s1 := []int{1, 2, 3, 10, 11, 12}
    s2 := []int{4, 5, 6}
    s3 := s1[:2]
    s4 := append(s3[:2], s2...)
    fmt.Println(s1)
    fmt.Println(s4)

    [1 2 4 5 6 12]
    [1 2 4 5 6]