add enumerate() pipe (#87)

Author: dit-zy

README.md

@@ -340,6 +340,20 @@ Deduplicate values, using the given `key` function if provided.
 ```
 
 
+## `enumerate(start=0)`
+
+The builtin `enumerate()` as a Pipe:
+
+```python
+>>> from pipe import enumerate
+>>> list(['apple', 'banana', 'citron'] | enumerate)
+[(0, 'apple'), (1, 'banana'), (2, 'citron')]
+>>> list(['car', 'truck', 'motorcycle', 'bus', 'train'] | enumerate(start=6))
+[(6, 'car'), (7, 'truck'), (8, 'motorcycle'), (9, 'bus'), (10, 'train')]
+
+```
+
+
 ## `filter(predicate)`
 
 Alias for `where(predicate)`, see `where(predicate)`.

pipe.py

@@ -102,6 +102,9 @@ def uniq(iterable, key=lambda x: x):
         prevkey = itemkey
 
 
+enumerate = Pipe(builtins.enumerate)
+
+
 @Pipe
 def permutations(iterable, r=None):
     # permutations('ABCD', 2) --> AB AC AD BA BC BD CA CB CD DA DB DC

tests/test_pipe.py

@@ -32,3 +32,9 @@ def test_netcat():
     for packet in data | pipe.netcat("python.org", 80):
         response += packet.decode("UTF-8")
     assert "HTTP" in response
+
+
+def test_enumerate():
+    data = [4, "abc", {"key": "value"}]
+    expected = [(5, 4), (6, "abc"), (7, {"key": "value"})]
+    assert list(data | pipe.enumerate(start=5)) == expected