Merge branch 'pr/2'

snippets/count_by.md

@@ -1,5 +1,7 @@
 ### count_by
 
+:information_source: Already implemented via `collections.Counter`
+
 Groups the elements of a list based on the given function and returns the count of elements in each group.
 
 Use `map()` to map the values of the list using the given function. Iterate over the map and increase the the elements count each time it occurs.

snippets/difference_by.md

@@ -0,0 +1,12 @@
+### difference_by
+``` python
+def difference_by(a, b, fn):
+    b = set(map(fn,b))
+    return [item for item in a if fn(item) not in b]
+```
+
+```python
+from math import floor
+difference_by([2.1, 1.2], [2.3, 3.4],floor) # [1.2]
+difference_by([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], lambda v : v['x']) # [ { x: 2 } ]
+```

snippets/spread.md

@@ -1,6 +1,6 @@
 ### spread
 
-Implements javascript's spread syntax as a function. Flattens the list(non-deep) and returns an list.
+Implements javascript's `[].concat(...arr)`. Flattens the list(non-deep) and returns an list.
 
 ```python
 def spread(arg):

static-parts/readme-start.md

@@ -2,6 +2,7 @@
 
 # 30-seconds-of-python-code
 [![License](https://img.shields.io/aur/license/yaourt.svg)](https://github.com/kriadmin/30-seconds-of-python-code/blob/master/LICENSE) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-4FB999.svg)](https://gitter.im/30-seconds-of-python-code/Lobby) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com) [![Travis Build](https://travis-ci.org/kriadmin/30-seconds-of-python-code.svg?branch=master)](https://travis-ci.org/kriadmin/30-seconds-of-python-code) [![Insight.io](https://img.shields.io/badge/insight.io-Ready-brightgreen.svg)](https://insight.io/github.com/kriadmin/30-seconds-of-python-code/tree/master/?source=0) [![js-semistandard-style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard)
+[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgithub.com%2Fkriadmin%2F30-seconds-of-python-code.svg?type=shield)](https://app.fossa.io/projects/git%2Bgithub.com%2Fkriadmin%2F30-seconds-of-python-code?ref=badge_shield)
 
 >Python implementation of 30-seconds-of-code.