intermediate python

SoniaComp · SoniaComp · commit 69337e34c274 · 2021-01-29T23:57:16.000+09:00
diff --git a/python/intermediate/12_collections.py b/python/intermediate/12_collections.py
@@ -0,0 +1,47 @@
+from collections import defaultdict
+
+# defaultdict you do not need to check whether a key is present or not
+# default dict&#44032; &#54200;&#54620;&#51216;!!!
+colours = (
+    ('Yasoob', 'Yellow'),
+    ('Ali', 'Blue'),
+    ('Arham', 'Green'),
+    ('Ali', 'Black'),
+    ('Yasoob', 'Red'),
+    ('Ahmed', 'Silver'),
+)
+
+favourite_colours = defaultdict(list)
+
+for name, colour in colours:
+    favourite_colours[name].append(colour)
+
+print(favourite_colours)
+
+# output
+# defaultdict(<type 'list'>,
+#    {'Arham': ['Green'],
+#     'Yasoob': ['Yellow', 'Red'],
+#     'Ahmed': ['Silver'],
+#     'Ali': ['Blue', 'Black']
+# })
+
+from collections import defaultdict
+tree = lambda: defaultdict(tree)
+some_dict = tree()
+some_dict['colours']['favourite'] = "yellow"
+# Works fine
+import json
+print(json.dumps(some_dict))
+# Output: {"colours": {"favourite": "yellow"}}
+
+from collections import OrderedDict
+
+colours = OrderedDict([("Red", 198), ("Green", 170), ("Blue", 160)])
+for key, value in colours.items():
+    print(key, value)
+# Output:
+#   Red 198
+#   Green 170
+#   Blue 160
+# Insertion order is preserved
diff --git a/python/intermediate/12_collections_counter.py b/python/intermediate/12_collections_counter.py
@@ -0,0 +1,23 @@
+from collections import Counter
+
+colours = (
+    ('Yasoob', 'Yellow'),
+    ('Ali', 'Blue'),
+    ('Arham', 'Green'),
+    ('Ali', 'Black'),
+    ('Yasoob', 'Red'),
+    ('Ahmed', 'Silver'),
+)
+
+favs = Counter(name for name, colour in colours)
+print(favs)
+# Output: Counter({
+#    'Yasoob': 2,
+#    'Ali': 2,
+#    'Arham': 1,
+#    'Ahmed': 1
+# })
+
+with open('filename', 'rb') as f:
+    line_count = Counter(f)
+print(line_count)
diff --git a/python/intermediate/12_collections_deque.py b/python/intermediate/12_collections_deque.py
@@ -0,0 +1,38 @@
+from collections import deque
+
+## &#44050; &#45347;&#44592;
+d = deque()
+d.append('1')
+d.append('2')
+d.append('3')
+
+print(len(d))
+# Output: 3
+
+print(d[0])
+# Output: '1'
+
+print(d[-1])
+# Output: '3'
+
+d = deque([1,2,3,4,5])
+d.extendleft([0])
+d.extend([6,7,8])
+print(d)
+# Output: deque([0, 1, 2, 3, 4, 5, 6, 7, 8])
+
+
+## &#44050; &#48764;&#44592;
+
+d = deque(range(5))
+print(len(d))
+# Output: 5
+
+d.popleft()
+# Output: 0
+
+d.pop()
+# Output: 4
+
+print(d)
+# Output: deque([1, 2, 3])
diff --git a/python/intermediate/12_collections_enum.py b/python/intermediate/12_collections_enum.py
@@ -0,0 +1,29 @@
+from collections import namedtuple
+from enum import Enum
+
+class Species(Enum):
+    cat = 1
+    dog = 2
+    horse = 3
+    aardvark = 4
+    butterfly = 5
+    owl = 6
+    platypus = 7
+    dragon = 8
+    unicorn = 9
+    # The list goes on and on...
+
+    # But we don't really care about age, so we can use an alias.
+    kitten = 1
+    puppy = 2
+
+Animal = namedtuple('Animal', 'name age type')
+perry = Animal(name="Perry", age=31, type=Species.cat)
+drogon = Animal(name="Drogon", age=4, type=Species.dragon)
+tom = Animal(name="Tom", age=75, type=Species.cat)
+charlie = Animal(name="Charlie", age=2, type=Species.kitten)
+
+# And now, some tests.
+charlie.type == tom.type
+True
+charlie.type
diff --git a/python/intermediate/12_collections_namedtuple.py b/python/intermediate/12_collections_namedtuple.py
@@ -0,0 +1,36 @@
+from collections import namedtuple
+#  you can not reassign an item in a tuple. In order to access the value in a tuple you use integer indexes like:
+
+
+Animal = namedtuple('Animal', 'name age type')
+perry = Animal(name="perry", age=31, type="cat")
+
+print(perry)
+# Output: Animal(name='perry', age=31, type='cat')
+
+print(perry.name)
+# Output: 'perry'
+
+from collections import namedtuple
+
+Animal = namedtuple('Animal', 'name age type')
+perry = Animal(name="perry", age=31, type="cat")
+perry.age = 42
+
+# Output: Traceback (most recent call last):
+#            File "", line 1, in
+#         AttributeError: can't set attribute
+
+from collections import namedtuple
+
+Animal = namedtuple('Animal', 'name age type')
+perry = Animal(name="perry", age=31, type="cat")
+print(perry[0])
+# Output: perry
+
+from collections import namedtuple
+
+Animal = namedtuple('Animal', 'name age type')
+perry = Animal(name="Perry", age=31, type="cat")
+print(perry._asdict())
+# Output: OrderedDict([('name', 'Perry'), ('age', 31), ..
