Add some more about ranges

Nim-for-Python-Programmers.md

@@ -133,7 +133,33 @@ So, when using inheritance, be sure to inherit using refs, unless you know what
 
 ### Ranges
 
-The syntax for ranges is different. a[x:y] becomes a[x..<y]
+In Python, simple integer for loops use the `range` generator function. For the 1- and 2- argument forms of this function, nim's [`..` iterator](https://nim-lang.org/docs/system.html#...i%2CT%2CT) works almost the same way:
+
+``` Nim
+for i in ..10:
+  echo i  # Prints 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
+
+for i in 5..10:
+  echo i  # Prints 5, 6, 7, 8, 9, 10
+```
+
+Note that the `..` operator includes the end of the range, whereas Python's `range(a, b)` does not include `b`. If you prefer this behavior, use the [`..<` iterator](https://nim-lang.org/docs/system.html#..%3C.i%2CT%2CT) instead:
+
+``` Nim
+for i in ..<10:
+  echo i  # Prints 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
+```
+
+Python's `range()` also has an optional third parameter, which is the value to increment by each step, which can be positive or negative. If you need this behavior, use the [`countup`](https://nim-lang.org/docs/system.html#countup.i%2CT%2CT%2CPositive) or [`countdown`](https://nim-lang.org/docs/system.html#countdown.i%2CT%2CT%2CPositive) iterators:
+
+``` Nim
+for i in countup(1, 10, 2):
+  echo i  # Prints 1, 3, 5, 7, 9
+```
+
+### Python slices
+
+The syntax for slice ranges is different. a[x:y] becomes a[x..<y].
 Also, a[x..y] is inclusive.
 ``` Nim
 let a = @[1,2,3,4]
@@ -143,6 +169,7 @@ a[0..<2] # returns @[1, 2]
 a[0..3]  # returns @[1, 2, 3, 4]
 ```
 
+
 ### Python strings
 
 Use double quotes: "foo" or """foo""", not 'foo'