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@LarynQi
Last active Jul 9, 2020
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CS61A SU20 Discussion 05
import doctest
import sys
import argparse
"""
---USAGE---
python3 disc05.py <name_of_function>
e.g python3 disc05.py height
---NOTES---
- if you pass all the doctests, you will get no terminal output
- if you want to see the verbose output (all output shown even if the function is correct), run this:
python3 disc05.py <name_of_function> -v
- if you want to test all of your functions, run this:
python3 disc05.py all
"""
### Discussion 05 ###
#########
# Trees
#########
# Q1.1
def height(t):
"""Return the height of a tree.
>>> t = tree(3, [tree(5, [tree(1)]), tree(2)])
>>> height(t)
2
"""
"*** UNCOMMENT SKELETON ***"
# if ____________________:
# ____________________
# ________________________________________
# Q1.2
def square_tree(t):
"""Return a tree with the square of every element in t
>>> numbers = tree(1,
... [tree(2,
... [tree(3),
... tree(4)]),
... tree(5,
... [tree(6,
... [tree(7)]),
... tree(8)])])
>>> print_tree(square_tree(numbers))
1
4
9
16
25
36
49
64
"""
"*** YOUR CODE HERE ***"
# Q1.3
def find_path(tree, x):
"""
>>> t = tree(2, [tree(7, [tree(3), tree(6, [tree(5), tree(11)])] ), tree(15)])
>>> find_path(t, 5)
[2, 7, 6, 5]
>>> find_path(t, 10) # returns None
"""
"*** UNCOMMENT SKELETON ***"
# if _____________________________:
# return _____________________________
# _____________________________:
# path = _____________________________
# if _____________________________:
# return _____________________________
# Q1.4
# Don't test this function until you've tried filling out the blanks,
# since the output will show you the correct answers.
def tree_wwpd():
"""
>>> t = tree(1, [tree(2), tree(3)])
>>> label(t)
____________________
>>> t[0]
____________________
>>> label(branches(t)[0])
____________________
>>> label(branches(t))
____________________
>>> is_leaf(t[1:][1])
____________________
>>> [label(b) for b in branches(t)]
____________________
>>> branches(tree(2, tree(t, [])))[0] # Challenge
____________________
"""
pass
#########
# Mutation
#########
"""
>>> pizza = ['cheese', 'mushrooms']
>>> new_pizza = pizza + ['onions'] # creates a new Python list
>>> new_pizza
['cheese', 'mushrooms', 'onions']
>>> pizza # the original list is unmodified
['cheese', 'mushrooms']
>>> pizza.append('onions')
>>> pizza
['cheese', 'mushrooms', 'onions']
>>> pizza[1] = 'tomatoes'
>>> pizza
['cheese', 'tomatoes', 'onions']
"""
# Q2.1
# Don't test this function until you've tried filling out the blanks,
# since the output will show you the correct answers.
def list_wwpd():
"""
>>> lst1 = [1, 2, 3]
____________________
>>> lst2 = lst1
____________________
>>> lst1 is lst2
____________________
>>> lst2.extend([5, 6])
____________________
>>> lst1[4]
____________________
>>> lst1.append([-1, 0, 1])
____________________
>>> -1 in lst1
____________________
>>> lst2[5]
____________________
>>> lst3 = lst2[:]
____________________
>>> lst3.insert(3, lst2.pop(3))
____________________
>>> len(lst1)
____________________
>>> lst1[4] is lst3[6]
____________________
>>> lst3[lst2[4][1]]
____________________
>>> lst1[:3] is lst2[:3]
____________________
>>> lst1[:3] == lst2[:3]
____________________
>>> x = (1, 2, [4, 5, 6])
____________________
>>> x[2] = [3, 5, 6]
____________________
>>> x
____________________
>>> x[2][0] = 3
____________________
>>> x
____________________
"""
pass
# Q2.2
def add_this_many(x, el, lst):
"""Adds el to the end of lst the number of times x occurs
in lst.
>>> lst = [1, 2, 4, 2, 1]
>>> add_this_many(1, 5, lst)
>>> lst
[1, 2, 4, 2, 1, 5, 5]
>>> add_this_many(2, 2, lst)
>>> lst
[1, 2, 4, 2, 1, 5, 5, 2, 2]
"""
"*** UNCOMMENT SKELETON ***"
# count = 0
# ____________________:
# ____________________:
# ____________________
# ____________________:
# ____________________
# ____________________
# Q2.3
def group_by(s, fn):
"""
>>> group_by([12, 23, 14, 45], lambda p: p // 10)
{1: [12, 14], 2: [23], 4: [45]}
>>> result = group_by(range(-3, 4), lambda x: x * x)
>>> {key:result[key] for key in sorted(result.keys())} # sorting by keys in increasing order
{0: [0], 1: [-1, 1], 4: [-2, 2], 9: [-3, 3]}
"""
"*** UNCOMMENT SKELETON ***"
# grouped = {}
# ____________________:
# ____________________
# if ____________________:
# ____________________
# else:
# ____________________
# return grouped
# Quiz
# Part a
def partition_options(total, biggest):
"""
>>> partition_options(2, 2)
[[2], [1, 1]]
>>> partition_options(3, 3)
[[3], [2, 1], [1, 1, 1]]
>>> partition_options(4, 3)
[[3, 1], [2, 2], [2, 1, 1], [1, 1, 1, 1]]
"""
"*** UNCOMMENT SKELETON ***"
# if _________________________________________________________:
# return _________________________________
# elif _______________________________________________________:
# return _________________________________
# else:
# with_biggest = __________________________________________
# without_biggest = _______________________________________
# ____________ = [[_________]______________________________]
# return with_biggest + without_biggest
# Part b
def min_elements(T, lst):
"""
>>> min_elements(10, [4, 2, 1]) # 4 + 4 + 2
3
>>> min_elements(12, [9, 4, 1]) # 4 + 4 + 4
3
>>> min_elements(0, [1, 2, 3])
0
"""
"*** UNCOMMENT SKELETON ***"
# if _________________________________________________________:
# return _________________________________
# return _________________________________________________________________________________
# Tree ADT
def tree(label, branches=[]):
"""Construct a tree with the given label value and a list of branches."""
for branch in branches:
assert is_tree(branch), 'branches must be trees'
return [label] + list(branches)
def label(tree):
"""Return the label value of a tree."""
return tree[0]
def branches(tree):
"""Return the list of branches of the given tree."""
return tree[1:]
def is_tree(tree):
"""Returns True if the given tree is a tree, and False otherwise."""
if type(tree) != list or len(tree) < 1:
return False
for branch in branches(tree):
if not is_tree(branch):
return False
return True
def is_leaf(tree):
"""Returns True if the given tree's list of branches is empty, and False
otherwise.
"""
return not branches(tree)
def print_tree(t, indent=0):
"""Print a representation of this tree in which each node is
indented by two spaces times its depth from the root.
>>> print_tree(tree(1))
1
>>> print_tree(tree(1, [tree(2)]))
1
2
>>> numbers = tree(1, [tree(2), tree(3, [tree(4), tree(5)]), tree(6, [tree(7)])])
>>> print_tree(numbers)
1
2
3
4
5
6
7
"""
print(' ' * indent + str(label(t)))
for b in branches(t):
print_tree(b, indent + 1)
def copy_tree(t):
"""Returns a copy of t. Only for testing purposes.
>>> t = tree(5)
>>> copy = copy_tree(t)
>>> t = tree(6)
>>> print_tree(copy)
5
"""
return tree(label(t), [copy_tree(b) for b in branches(t)])
### For running tests only. Not part of discussion content ###
parser = argparse.ArgumentParser(description="Test your work")
parser.add_argument("func", metavar="function_to_test", help="Function to be tested")
parser.add_argument("-v", dest="v", action="store_const", const=True, default=False, help="Verbose output")
args = parser.parse_args()
try:
if args.func == "all":
if args.v:
doctest.testmod(verbose=True)
else:
doctest.testmod()
else:
if args.v:
doctest.run_docstring_examples(globals()[args.func], globals(), verbose=True, name=args.func)
else:
doctest.run_docstring_examples(globals()[args.func], globals(), name=args.func)
except:
sys.exit("Invalid Arguments")
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