This section has 6 questions. For each question, read the code and type your answer under the Answer heading. You should answer the questions without running the code or consulting external resources to determine the output.
You have 15 minutes to complete this section.
Question A1
Assume you have a list of names, each entry has a first and last name. Write a list comprehension to generate the permutations of names, excluding the last names that are longer than 7 characters.
For example, names = ["John Smith", "Sally Anderson", "Ashwin Long", "Mandy Kim"], returns
["John Smith", "John Long", "John Kim", "Sally Smith", "Sally Long", "Sally Kim", "Ashwin Smith", "Ashwin Long", "Ashwin Kim", "Mandy Smith", "Mandy Long", "Mandy Kim"]You answer should be a single line of code. Please assume that there is an existing variable called names containing a list of input names.
Question A2
What are the values of slice1, slice2, slice3, and slice4 at the end of this code block?
ar = [range(5, 30, 5)]
slice1 = ar[2:2]
slice2 = ar[:2]
slice3 = ar[::-1]
slice4 = ar[1:4:2]Question A3
What error does the following code return and how do you fix it?
class Equity:
num_identifiers: int = 0
identifiers = []
def __init__(self, identifier, name):
self._identifier = identifier
self._name = name
Equity.track_identifier(identifier)
def track_identifier(cls, identifier):
cls.num_identifiers += 1
cls.identifiers.append(identifier)
eq1 = Equity("identifier1", "Apple")
eq2 = Equity("identifier2", "Google")
print("Total number of equities {Equity.num_identifiers}")Question A4
What are the values of list1, list2, list3, and list4 at the end of this code block?
list1 = [(1, 2, 3, 4), (20, 40, 60), (100, 95, 90)]
list2 = list(list1)
list3 = list2
list1[1].append(80)
list1.append(5500)
list2[0] = (0, 1, 2, 3, 4, 5)
list3[1].remove(40)
list4 = list2.append(4200)Question A5
What is printed when you run the code below?
def f():
x = []
def g(y=None):
if not x:
x.append(y)
elif y:
x.append(x[len(x)-1] + y)
return x
return g
h = f()
h(15)
h(25)
h(3)
print(h(2))Question A6
Given the code below, what is returned for the best finance stock and best overall stock? Briefly explain your answer.
def add_tech_stocks(curr_stocks: dict) -> dict:
stocks = curr_stocks
stocks["APPL"] = 124.40
stocks["GOOG"] = 1569.15
stocks["AMZN"] = 3442.93
return stocks
def best_stock(stocks: dict) -> str:
curr_max = 0
curr_ticker = None
for key, value in stocks.items():
if value > curr_max:
curr_ticker = key
curr_max = value
return curr_ticker
finance_stocks = {"GS": 214.12, "MS": 10.61, "JPM": 102.44}
all_stocks = add_tech_stocks(finance_stocks)
best_finance = best_stock(finance_stocks)
best_overall = best_stock(all_stocks)这是一组典型的 Python 基础面试题，重点考察切片、列表与对象的引用关系、闭包、字典遍历以及类方法 / 实例方法的使用。做题时要特别注意可变对象的共享与原地修改，例如 list 与 tuple 混用时，浅拷贝不会复制内部嵌套对象；函数返回值和 print 输出也容易被混淆。第 3 题还涉及方法装饰与调用方式错误，理解类中成员函数应该如何定义和调用，是正确排错的关键。
