Merge branch 'master' into fix_max_n

snippets/compact.md

@@ -6,9 +6,9 @@ Use `filter()` to filter out falsey values (False, None, 0, and "").
 
 ```python
 def compact(arr):
-    return list(filter(lambda x: bool(x), arr))
+    return list(filter(bool, arr))
 ```
 
 ``` python
 compact([0, 1, False, 2, '', 3, 'a', 's', 34]) # [ 1, 2, 3, 'a', 's', 34 ]
-```
+```

snippets/difference.md

@@ -1,14 +1,13 @@
 ### difference
 
-Returns the difference between two arrays.
+Returns the difference between two iterables.
 
-Create a `set` from `b`, then use list comprehension to only keep values not contained in `b`
+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]
+    return [item for item in a if item not in b]
 ```
 ``` python
 difference([1, 2, 3], [1, 2, 4]) # [3]
-```
+```

snippets/is_lower_case.md

@@ -5,8 +5,8 @@ Checks if a string is lower case.
 Convert the given string to lower case, using `str.lower()` method and compare it to the original.
 
 ```python
-def is_lower_case(str):
-    return str == str.lower()
+def is_lower_case(string):
+    return string == string.lower()
 ```
 
 ```python

snippets/is_upper_case.md

@@ -5,8 +5,8 @@ Checks if a string is upper case.
 Convert the given string to upper case, using `str.upper()` method and compare it to the original.
 
 ```python
-def is_upper_case(str):
-    return str == str.upper()
+def is_upper_case(string):
+    return string == string.upper()
 ```
 
 ```python