Chapter 10

CodeMouse92 · CodeMouse92 · commit dac706a8eece · 2022-05-25T10:25:27.000-05:00
diff --git a/Ch10/coroutine_sequence.py b/Ch10/coroutine_sequence.py
@@ -0,0 +1,18 @@
+def coroutine():
+    ret = None
+    while True:
+        print("...")
+        recv = yield ret
+        print(f"recv: {recv}")
+        ret = recv
+
+
+co = coroutine()
+current = co.send(None)
+print(f"current (ret): {current}")
+
+for i in range(10):
+    current = co.send(i)
+    print(f"current (ret): {current}")
+
+co.close()
diff --git a/Ch10/divis_by_three.py b/Ch10/divis_by_three.py
@@ -0,0 +1,2 @@
+# divis_by_three = (n for n in range(100) if n % 3 == 0)
+divis_by_three = (n if n % 3 == 0 else "redacted" for n in range(100))
diff --git a/Ch10/license_generator.py b/Ch10/license_generator.py
@@ -0,0 +1,38 @@
+from itertools import product
+from string import ascii_uppercase as alphabet
+
+
+def gen_license_plates():
+    for letters in product(alphabet, repeat=3):
+        letters = "".join(letters)
+        if letters == 'GOV':
+            continue
+
+        for numbers in range(1000):
+            yield f'{letters} {numbers:03}'
+
+
+license_plates = gen_license_plates()
+
+# for plate in license_plates:
+#     print(plate)
+
+registrations = {}
+
+
+def new_registration(owner):
+    if owner not in registrations:
+        plate = next(license_plates)
+        registrations[owner] = plate
+        return plate
+    return None
+
+
+# Fast-forward through several results for testing purposes.
+for _ in range(4441888):
+    next(license_plates)
+
+name = "Jason C. McDonald"
+my_plate = new_registration(name)
+print(my_plate)
+print(registrations[name])
diff --git a/Ch10/license_plates.py b/Ch10/license_plates.py
@@ -0,0 +1,44 @@
+from itertools import product
+from string import ascii_uppercase as alphabet
+
+# def license_plates():
+#     for num in range(1000):
+#         yield f"ABC {num:03}"
+
+# license_plates = (
+#     f"ABC {number:03}"
+#     for number in range(1000)
+# )
+
+license_plates = (
+    f'{letters} {number:03}'
+    for letters in (
+        "".join(chars)
+        for chars in product(alphabet, repeat=3)
+    )
+    if letters != 'GOV'
+    for number in range(1000)
+)
+
+# for plate in license_plates():
+# for plate in license_plates:
+#     print(plate)
+
+registrations = {}
+
+
+def new_registration(owner):
+    if owner not in registrations:
+        plate = next(license_plates)
+        registrations[owner] = plate
+        return True
+    return False
+
+
+# Fast-forward through several results for testing purposes.
+for _ in range(4441888):
+    next(license_plates)
+
+name = "Jason C. McDonald"
+my_plate = new_registration(name)
+print(registrations[name])
diff --git a/Ch10/odd_remainers.py b/Ch10/odd_remainers.py
@@ -0,0 +1,2 @@
+odd_remainders = {100 % divisor for divisor in range(1, 100, 2)}
+print(odd_remainders)
diff --git a/Ch10/orders_comprehension.py b/Ch10/orders_comprehension.py
@@ -0,0 +1,7 @@
+orders = ['cold brew', 'lemongrass tea', 'chai latte', 'medium drip',
+         'french press', 'mocha cappuccino', 'pumpkin spice latte',
+         'double-shot espresso', 'dark roast drip', 'americano']
+
+drip_orders = [order for order in orders if 'drip' in order]
+
+print(f'There are {len(drip_orders)} orders for drip coffee.')
diff --git a/Ch10/sleepy.py b/Ch10/sleepy.py
@@ -0,0 +1,12 @@
+import time
+# sleepy = ['no pause', time.sleep(1), time.sleep(2)]
+# ...three second pause...
+# print(sleepy[0])  # prints 'no pause'
+
+sleepy = (time.sleep(t) for t in range(0, 3))
+print("Calling...")
+next(sleepy)
+print("Done!")
+
+# Not lazy
+sleepy = (time.sleep(t) for t in [1, 2, 3, 4, 5])
diff --git a/Ch10/squares_dictionary_comprehension.py b/Ch10/squares_dictionary_comprehension.py
@@ -0,0 +1,4 @@
+squares = {n : n ** 2 for n in range(1, 101)}
+print(squares[2])
+print(squares[7])
+print(squares[11])
diff --git a/Ch10/traffic_bikers_generator.py b/Ch10/traffic_bikers_generator.py
@@ -0,0 +1,28 @@
+from random import choice, randint
+
+colors = ['red', 'green', 'blue', 'silver', 'white', 'black']
+vehicles = ['car', 'truck', 'semi', 'motorcycle', None]
+
+
+def biker_gang():
+    for _ in range(randint(2, 10)):
+        color = choice(colors)
+        yield f"{color} motorcycle"
+
+
+def traffic():
+    while True:
+        if randint(1, 50) == 50:
+            yield from biker_gang()
+            continue
+
+        vehicle = choice(vehicles)
+        color = choice(colors)
+        yield f"{color} {vehicle}"
+
+
+count = 0
+for count, vehicle in enumerate(traffic()):
+    print(f"{vehicle}")
+    if count == 100:
+        break
diff --git a/Ch10/traffic_colors_coroutine.py b/Ch10/traffic_colors_coroutine.py
@@ -0,0 +1,35 @@
+from random import choice
+
+
+def color_counter(color):
+    matches = 0
+    while True:
+        vehicle = yield matches
+        if color in vehicle:
+            matches += 1
+
+
+colors = ['red', 'green', 'blue', 'silver', 'white', 'black']
+vehicles = ['car', 'truck', 'semi', 'motorcycle']
+
+
+def traffic():
+    while True:
+        vehicle = choice(vehicles)
+        color = choice(colors)
+        yield f"{color} {vehicle}"
+
+
+counter = color_counter('red')
+# counter.send(None)  # prime the coroutine
+next(counter)  # prime the coroutine
+
+matches = 0
+for count, vehicle in enumerate(traffic(), start=1):
+    if count < 100:
+        matches = counter.send(vehicle)
+    else:
+        counter.close()
+        break
+
+print(f"There were {matches} matches.")
diff --git a/Ch10/traffic_generator_class.py b/Ch10/traffic_generator_class.py
@@ -0,0 +1,42 @@
+from random import choice
+
+colors = ['red', 'green', 'blue', 'silver', 'white', 'black']
+vehicles = ['car', 'truck', 'semi', 'motorcycle', None]
+
+
+# as an iterator class
+
+# class Traffic:
+#     def __iter__(self):
+#         return self
+
+#     def __next__(self):
+#         vehicle = choice(vehicles)
+
+#         if vehicle is None:
+#             raise StopIteration
+
+#         color = choice(colors)
+
+#         return f"{color} {vehicle}"
+
+# as a generator function
+
+def traffic():
+    while True:
+        vehicle = choice(vehicles)
+
+        if vehicle is None:
+            return
+
+        color = choice(colors)
+        yield f"{color} {vehicle}"
+
+
+# merge into traffic
+count = 0
+# for count, vehicle in enumerate(Traffic(), start=1):
+for count, vehicle in enumerate(traffic(), start=1):
+    print(f"Wait for {vehicle}...")
+
+print(f"Merged after {count} vehicles!")
diff --git a/Ch10/traffic_generator_throw.py b/Ch10/traffic_generator_throw.py
@@ -0,0 +1,40 @@
+from random import choice
+colors = ['red', 'green', 'blue', 'silver', 'white', 'black']
+vehicles = ['car', 'truck', 'semi', 'motorcycle', None]
+
+
+def traffic():
+    while True:
+        vehicle = choice(vehicles)
+        color = choice(colors)
+        try:
+            yield f"{color} {vehicle}"
+        except ValueError:
+            print(f"Skipping {color} {vehicle}...")
+            continue
+        except GeneratorExit:
+            print("No more vehicles.")
+            raise
+
+
+def wash_vehicle(vehicle):
+    if 'semi' in vehicle:
+        raise ValueError("Cannot wash vehicle.")
+    print(f"Washing {vehicle}.")
+
+
+def car_wash(traffic, limit):
+    count = 0
+    for vehicle in traffic:
+        try:
+            wash_vehicle(vehicle)
+        except Exception as e:
+            traffic.throw(e)
+        else:
+            count += 1
+        if count >= limit:
+            traffic.close()
+
+
+queue = traffic()
+car_wash(queue, 10)
diff --git a/Ch10/traffic_infinite_generator.py b/Ch10/traffic_infinite_generator.py
@@ -0,0 +1,28 @@
+from random import choice
+
+colors = ['red', 'green', 'blue', 'silver', 'white', 'black']
+vehicles = ['car', 'truck', 'semi', 'motorcycle', None]
+
+
+def traffic():
+    while True:
+        vehicle = choice(vehicles)
+        color = choice(colors)
+        try:
+            yield f"{color} {vehicle}"
+        except GeneratorExit:
+            print("No more vehicles.")
+            raise
+
+
+def car_wash(traffic, limit):
+    count = 0
+    for vehicle in traffic:
+        print(f"Washing {vehicle}.")
+        count += 1
+        if count >= limit:
+            traffic.close()
+
+
+queue = traffic()
+car_wash(queue, 10)

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+# divis_by_three = (n for n in range(100) if n % 3 == 0)`
	`2`	`+divis_by_three = (n if n % 3 == 0 else "redacted" for n in range(100))`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+odd_remainders = {100 % divisor for divisor in range(1, 100, 2)}`
	`2`	`+print(odd_remainders)`