Merge branch 'master' of https://github.com/guidiego/python-cookbook-examples

Author: Guilherme Diego

forloop.py

@@ -0,0 +1,5 @@
+s = "a string to examine"
+for i in range(len(s)):
+    for j in range(i+1, len(s)):
+        if s[i] == s[j]:
+            answer = (i, j)

p14-2.py

@@ -0,0 +1,17 @@
+import heapq
+
+
+portfolio = [
+    {'name': 'IBM', 'shares': 100, 'price': 91.1},
+    {'name': 'AAPL', 'shares': 50, 'price': 543.22},
+    {'name': 'FB', 'shares': 200, 'price': 21.09},
+    {'name': 'HPQ', 'shares': 35, 'price': 31.75},
+    {'name': 'YHOO', 'shares': 45, 'price': 16.35},
+    {'name': 'ACME', 'shares': 75, 'price': 115.65},
+]
+
+cheap = heapq.nsmallest(3, portfolio, key=lambda s: s['price'])
+expensive = heapq.nlargest(3, portfolio, key=lambda s: s['price'])
+
+print('Cheap shares: ', cheap, '\n')
+print('Expensive shares: ', expensive)

p14.py

@@ -0,0 +1,6 @@
+import heapq
+
+nums = [1, 8, 2, 23, 7, -4, 18, 23, 42, 37, 2]
+
+print(heapq.nlargest(3, nums))
+print(heapq.nsmallest(3, nums))

p15.py

@@ -0,0 +1,34 @@
+import heapq
+
+
+class PriorityQueue:
+    def __init__(self):
+        self.queue = []
+        self._index = 0
+
+    def push(self, item, priority):
+        heapq.heappush(self.queue, (-priority, self._index, item))
+        self._index += 1
+
+    def pop(self):
+        return heapq.heappop(self.queue)[-1]
+
+if __name__ == '__main__':
+
+    class Item:
+        def __init__(self, name):
+            self.name = name
+
+        def __repr__(self):
+            return 'Item({!r})'.format(self.name)
+
+    q = PriorityQueue()
+    q.push(Item('foo'), 1)
+    q.push(Item('bar'), 5)
+    q.push(Item('spam'), 4)
+    q.push(Item('grok'), 1)
+
+    print(q.pop())
+    print(q.pop())
+    print(q.pop())
+    print(q.pop())

p19.py

@@ -0,0 +1,39 @@
+a = {
+    'x': 1,
+    'y': 2,
+    'z': 3
+}
+
+b = {
+    'w': 10,
+    'x': 11,
+    'y': 2
+}
+
+c = {
+    'x': 4,
+    'u': 2
+}
+
+print('a: ', a)
+print('b: ', b)
+print('c: ', c)
+
+print('Commons items (items in a in b)')
+print(a.items() & b.items())
+print('Common keys (keys in a in b)')
+print(a.keys() & b.keys())
+print('Intersection (keys in a not in b)')
+print(a.keys() - b.keys())
+print('Intersection (keys in b not in a)')
+print(b.keys() - a.keys())
+print('Intersection (items in a not in c)')
+print(a.items() - c.items())
+print('Intersection (keys in a not in c)')
+print(a.keys() - c.keys())
+
+
+# cria um novo dicionario com determindas chaves removidas
+c = {key: a[key] for key in a.keys() - {'z', 'w'}}
+print('Removing specific keys {\'z\', \'w\'} from a')
+print(c)