add new adapters

Author: hamidb80

readme.md

@@ -230,6 +230,8 @@ iterrr "hello".items: # or "hello".items.iterrr:
 - `window`
 - `cycle`
 - `flatten`
+- `drop`
+- `take`
 
 **Usage**: 
 example:
@@ -245,7 +247,7 @@ matrix.items |> flatten().map(-it).cycle(11).group(4).toseq()
 ```
 result:
 ```nim
->> @[
+@[
   @[-1, -2, -3, -4], 
   @[-5, -6, -7, -8], 
   @[-9, -1, -2] 
@@ -304,8 +306,11 @@ you can send your donation to my [crypo wallets](https://github.com/hamidb80/ham
 improve existing code.
 
 ## Change Logs
-### `0.4.2` -> `0.4.3`:
-- add `window` adapter
+### `0.4.2` -> `0.4.4`:
+- add new adapters:
+  - `window`
+  - `take`
+  - `drop`
 
 ### `0.4.1` -> `0.4.2`:
 - optimize

src/iterrr/adapters.nim

@@ -81,6 +81,21 @@ iterator cycle*(loopItems: T; `limit`: int): T {.adapter.} =
         if `c` == `limit`:
           break cycleLoop
 
+iterator drop*(loopItems: T; `limit`: int): T {.adapter.} =
+  var `c` = 0
+  for it in loopItems:
+    inc `c`
+    if `c` > `limit`:
+      yield it
+
+iterator take*(loopItems: T; `limit`: int): T {.adapter.} =
+  var `c` = 0
+  for it in loopItems:
+    if `c` == `limit`: break
+    else: yield it
+    inc `c`
+
+
 iterator flatten*(loopItems: T): typeof loopItems[0] {.adapter.} =
   for it in loopItems:
     for it in it:

tests/test.nim

@@ -204,6 +204,12 @@ suite "adapters":
   test "cycle":
     check (1..3) |> cycle(7).toseq() == @[1, 2, 3, 1, 2, 3, 1]
 
+  test "drop":
+    check (1..7) |> drop(3).toseq() == @[4, 5, 6, 7]
+
+  test "take":
+    check (1..7) |> take(3).toseq() == @[1, 2, 3]
+
   test "flatten":
     check matrix.items |> flatten().toseq() == toseq(1..9)