Mon Oct 7 13:02:31 PDT 2024

_internal/targets.json

@@ -1 +1 @@
-[{"due": "10/4/24", "link": "lab/lab05/", "name": "Lab 05: Python Lists", "piazza_name": "Lab 05", "release": "9/30/24"}, {"due": "10/9/24", "link": "hw/hw05/", "name": "HW 05: Tree Recursion", "piazza_name": "HW 05", "release": "10/2/24"}, {"due": "10/16/24", "link": "proj/cats/", "name": "Cats", "piazza_name": "Cats", "release": "10/2/24"}]
+[{"due": "10/9/24", "link": "hw/hw05/", "name": "HW 05: Tree Recursion", "piazza_name": "HW 05", "release": "10/2/24"}, {"due": "10/11/24", "link": "lab/lab06/", "name": "Lab 06: Mutability", "piazza_name": "Lab 06", "release": "10/7/24"}, {"due": "10/16/24", "link": "proj/cats/", "name": "Cats", "piazza_name": "Cats", "release": "10/2/24"}]

assets/slides/10.py

@@ -0,0 +1,110 @@
+
+# Lists practice
+
+digits = [1, 8, 2, 8]
+8 in digits
+[1, 8] in digits
+1 in digits and 8 in digits
+
+for x in digits:
+    continue
+    #print(100 * x)
+
+def f(x):
+    for y in [x, x + 1, x + 2]:
+        print('this is y:', y)
+        if y > 0:
+            return y
+    return 1000
+
+def print_negatives(s):
+    for d in s:
+        d = -d
+        print(d)
+    print(s)
+    s = [2, 3, 4]
+    return s
+
+# Range practice
+
+def range_practice():
+    range(4)
+    list(range(4))
+    range(-2, 2)
+    list(range(-2, 2))
+    range(2, 100000000)  # 9 zeroes slows things down a lot
+    list(range(2, 100000000))
+    len(range(2, range(0, 23)[9]))
+
+def fib(n):
+    """Return the nth fibonnaci number.
+
+    >>> fib(0)
+    0
+    >>> fib(2)
+    1
+    >>> fib(10)
+    55
+    """
+    fib_number = 0
+    what_to_add = 1  # to get to the next fib number
+    for _ in range(n):
+        what_to_add, fib_number = fib_number, fib_number + what_to_add
+    return fib_number
+
+# List comprehension practice
+
+xs = range(-10, 11)
+ys = [x*x - 2*x + 1 for x in xs]
+
+xs_where_y_is_below_10 = [x for x in xs if x*x - 2*x + 1 < 10]
+xs_where_y_is_below_10 = [xs[i] for i in range(len(xs)) if ys[i] < 10]
+
+# Tree recursion practice
+
+goal = 21
+
+def play(strategy0, strategy1, n=0, who = 0, announce=False):
+    "Play twenty-one starting at n and return the index of the winner."
+    strategies = [strategy0, strategy1]
+    while n < goal:
+        n = n + strategies[who](n)
+        if announce:
+            print('Player', who, 'increases n to', n)
+        who = 1 - who
+    return who
+
+def two_strat(n):
+    "Always choose 2."
+    return 2
+
+def interactive(n):
+    "Ask the user."
+    choice = input('Pick 1, 2, or 3: ')
+    if choice in ['1', '2', '3']:
+        return int(choice)
+    else:
+        print('Invalid choice!')
+        return interactive(n)
+
+def best(n, other_strategy):
+    """Return an best strategy against other_strategy.
+
+    >>> beat_two_strat = lambda n: best(n, two_strat)
+    >>> winner(20, beat_two_strat, two_strat)
+    1
+    >>> winner(19, beat_two_strat, two_strat)
+    0
+    >>> winner(15, beat_two_strat, two_strat)
+    0
+    >>> winner(0, beat_two_strat, two_strat)
+    0
+    """
+    plan = lambda future_n: best(future_n, other_strategy)
+    for choice in range(1, 4):
+        if play(plan, other_strategy, n + choice, 1) == 0:
+            return choice
+    return 1
+
+perfect = lambda n: best(n, perfect)
+

assets/slides/11.py

@@ -0,0 +1,79 @@
+
+def box_pointer_example():
+    def f(s):
+        x = s[0]
+        return [x]
+
+    t = [3, [2+2, 5]]
+    u = [f(t[1]), t]
+    print(u)
+
+def double_eights(s):
+    """Return whether two consecutive items of list s are 8.
+
+    >>> double_eights([1, 2, 8, 8])
+    True
+    >>> double_eights([8, 8, 0])
+    True
+    >>> double_eights([5, 3, 8, 8, 3, 5])
+    True
+    >>> double_eights([2, 8, 4, 6, 8, 2])
+    False
+    """
+    for i in range(len(s)-1):
+        if s[i] == 8 and s[i+1] == 8:
+            return True
+    return False
+
+def double_eights_rec(s):
+    """Return whether two consecutive items of list s are 8.
+
+    >>> double_eights_rec([1, 2, 8, 8])
+    True
+    >>> double_eights_rec([8, 8, 0])
+    True
+    >>> double_eights_rec([5, 3, 8, 8, 3, 5])
+    True
+    >>> double_eights_rec([2, 8, 4, 6, 8, 2])
+    False
+    """
+    if s[:2] == [8, 8]:
+        return True
+    elif len(s) < 2:
+        return False
+    else:
+        return double_eights_rec(s[1:])
+
+min(range(10), key=lambda i: abs(50 ** 0.5 - i))
+sum([2, 3, 4], sum([20, 30, 40]))
+any([x > 10 for x in range(10)])
+
+xs = range(-10, 11)
+ys = [x*x - 2*x + 1 for x in xs]
+min(xs, key=lambda x: x*x - 2*x + 1)
+xs[min(range(len(xs)), key=lambda i: ys[i])]
+
+
+def park(n):
+    """Return the ways to park cars and motorcycles in n adjacent spots.
+
+    >>> park(1)
+    ['%', '.']
+    >>> park(2)
+    ['%%', '%.', '.%', '..', '<>']
+    >>> park(3)
+    ['%%%', '%%.', '%.%', '%..', '%<>', '.%%', '.%.', '..%', '...', '.<>', '<>%', '<>.']
+    >>> len(park(4))
+    29
+    """
+    if n < 0:
+        return []
+    elif n == 0:
+        return ['']
+    else:
+        return (['%'  + s for s in park(n-1)] +
+                ['.'  + s for s in park(n-1)] +
+                ['<>' + s for s in park(n-2)])
+
+
+

assets/slides/12.py

@@ -0,0 +1,48 @@
+xs = range(-10, 11)
+ys = [x*x - 2*x + 1 for x in xs]
+
+i = min(range(len(ys)), key=lambda i: ys[i])
+xs[min(range(len(xs)), key=lambda i: ys[i])]
+
+
+def park(n):
+    """Return the ways to park cars and motorcycles in n adjacent spots.
+
+    >>> park(1)
+    ['%', '.']
+    >>> park(2)
+    ['%%', '%.', '.%', '..', '<>']
+    >>> park(3)
+    ['%%%', '%%.', '%.%', '%..', '%<>', '.%%', '.%.', '..%', '...', '.<>', '<>%', '<>.']
+    >>> len(park(4))
+    29
+    """
+    if n < 0:
+        return []
+    elif n == 0:
+        return ['']
+    else:
+        return (['%'  + s for s in park(n-1)] +
+                ['.'  + s for s in park(n-1)] +
+                ['<>' + s for s in park(n-2)])
+
+
+def dict_demos():
+    numerals = {'I': 1, 'V': 5, 'X': 10}
+    numerals['X']
+    # numerals['X-ray']
+    # numerals[10]
+    len(numerals)
+    list(numerals)
+    numerals.values()
+    list(numerals.values())
+    sum(numerals.values())
+    dict([[3, 9], [4, 16]])
+    numerals.get('X', 0)
+    numerals.get('X-ray', 0)
+    numerals.get('X-ray')
+    {1: 2, 1: 3}
+    {[1]: 2}
+    {1: [2]}
+
+