From a11c0d44c1946b6466a0cede640ca656e8a95fa7 Mon Sep 17 00:00:00 2001
From: Rohit Tanwar <mst10041967@gmail.com>
Date: Sat, 20 Jan 2018 19:46:44 +0530
Subject: [PATCH] difference

---
 README.md                | 18 ++++++++++++++++++
 snippets/compact.md      |  1 +
 snippets/deep_flatten.md |  1 +
 snippets/difference.md   | 16 ++++++++++++++++
 4 files changed, 36 insertions(+)
 create mode 100644 snippets/difference.md

diff --git a/README.md b/README.md
index 76bf7fc8d..3afa85392 100644
--- a/README.md
+++ b/README.md
@@ -39,6 +39,7 @@ Use `filter()` to filter out falsey values (False, None, 0, and "").
 
 ```python 
 
+
 def compact(arr):
     return list(filter(lambda x: bool(x), arr))
 
@@ -116,12 +117,29 @@ def spread(arg):
 
 
 
+
 ```
 
 ```python
 deep_flatten([1, [2], [[3], 4], 5]) # [1,2,3,4,5]
 ```
 
+### difference
+
+Returns the difference between two arrays.
+
+Create a `set` from `b`, then use list comprehension to only keep values not contained in `b`
+
+```python 
+
+def difference(a, b):
+    b = set(b)
+    return [item for item in a if item not in b]
+
+```
+``` python
+difference([1, 2, 3], [1, 2, 4]) # [3]
+```
 ### gcd
 
 Calculates the greatest common divisor between two or more numbers/lists.
diff --git a/snippets/compact.md b/snippets/compact.md
index 477001202..0c3c43c4b 100644
--- a/snippets/compact.md
+++ b/snippets/compact.md
@@ -6,6 +6,7 @@ Use `filter()` to filter out falsey values (False, None, 0, and "").
 
 ```python 
 
+
 def compact(arr):
     return list(filter(lambda x: bool(x), arr))
 
diff --git a/snippets/deep_flatten.md b/snippets/deep_flatten.md
index 4f3d76b7b..b4ac9e6da 100644
--- a/snippets/deep_flatten.md
+++ b/snippets/deep_flatten.md
@@ -26,6 +26,7 @@ def spread(arg):
 
 
 
+
 ```
 
 ```python
diff --git a/snippets/difference.md b/snippets/difference.md
new file mode 100644
index 000000000..32c8db200
--- /dev/null
+++ b/snippets/difference.md
@@ -0,0 +1,16 @@
+### difference
+
+Returns the difference between two arrays.
+
+Create a `set` from `b`, then use list comprehension to only keep values not contained in `b`
+
+```python 
+
+def difference(a, b):
+    b = set(b)
+    return [item for item in a if item not in b]
+
+```
+``` python
+difference([1, 2, 3], [1, 2, 4]) # [3]
+```
\ No newline at end of file