Study Guides Questions and Answers

Study Guides Questions and Answers What is one similarity between print () and input()? Print & input similarity + 4 pts Both generate a string output + 4 pts Both built-in or standard library functions + 4 pts Correct, other than above + 1 pts Attempted but mostly incorrect or too vague + 0 pts Completely wrong or Blank - 2 pts Too Vague - 1 pts Mistake - 0.5 pts Minor mistake Whenever the Python interpreter needs to evaluate a name(of a variable, function, etc...), it searched for the name definition in this order: 1: __________ 2: __________ 3: __________ Three from the following 4: + 1.5 pts Local + 1.5 pts Global + 1.5 pts Module Import + 1.5 pts Built-in Order of Answers: + 1.5 pts Correct Order + 1 pts Partial Correct Order Explain the differences between 'import math' and 'from math import sqrt' or 'from math import*' import math vs from math import */sqrt + 5 pts "Import math" and "From math import " import all the functions/objects of the module while "from module import sqrt" imports the specific function/object. "From math import " and "From math import sqrt" allow the object to be referred to without including the module from which it was imported, which might lead to pollution of the namespace. + 4 pts Partially Correct. Did not correctly explain the meaning of from math import sqrt or * What is the main difference between print () and return? Given an example. Print vs Return + 2 pts Explain print + 2 pts Explain return + 2 pts Print example + 2 pts return example + 0 pts Blank In the expression: count %= count - offset + 2 which operator has the lowest precedence? Why? +4 pts Correct operator (%=) +4 pts Correct explanation: Since the modulo operator is chained with the assignment operator(which has lowest precedence), the %= will execute last. +0 pts Completely wrong Do the keys of a dictionary best model a list or a set? Dictionary keys: list vs sets + 5 pts [List or Set] Set + 5 pts [Uniqueness] Keys must be unique + 5 pts [Order] Keys and sets are unordered. + 5 pts [Mutability] Keys are immutable, and elements of a set have to be immutable + 2 pts General neutral / correct statements - 2 pts General incorrect statements + 1 pts Not blank. Give two examples of functionality/applications that you can do with a dictionary you can't do with a list. Two examples where you can use dictionaries but not lists + 5 pts Correct + 2.5 pts Relationships between keys and values + 2.5 pts Addressing values by key rather than index + 1 pts Partially Correct / Not Blank + 2.5 pts Keys are unique + 2.5 pts Dictionaries are unordered Given a value for a dictionary, is there a built-in way to lookup the corresponding key? Explain your answer. Lookup key by value in dictionary + 4 pts There is NOT a built-in way. + 4 pts Keys are unique while values are not. + 4 pts Many keys might have the same associated value. + 2 pts Keys are immutable while values are not. + 2 pts You can only use a key to lookup a value with built-ins. + 1 pts General correct comments about dictionaries not mentioned on other rubric points above. Why does Python provide so many different ways to structure & store data? What would happen if Python didn't provide data structures? Reasons for Structured Types +0 pts Completely wrong +4 pts Answered first question: many ways to associate/store data +4 pts Programs would have an unmanageable number of variables For the code below, draw a visual representation of the list, cs_courses: Course = namedtuple('Course', 'dept nurn title instr units') ics31 = Course ( 'ICS', '31','Intro to Programming', 'Alfaro', 4. 0) ics32 = Course ( 'ICS', '32','Programming with Libraries', 'Hermans', 4.0) cs_courses = [ics31, ics32] Visualization + 8 pts Correct + 1 pts cs_courses: index(0-1) & neg index(-1~-2) + 1 pts cs_courses: Structure: 2 Squares for each namedtuple + 2 pts For each cs_courses[x]: namedtuple: field names + 2 pts For each cs_courses[x]: namedtuple: field names: index(0-4) + 2 pts For cs_courses[1]: namedtuple: values for each field Give two examples of functionality/applications that you can do with a dictionary you can't do with a list. Two examples you can use dictionaries but not lists + 5 pts Correct + 2.5 pts Relationships between keys and values + 2.5 pts Addressing values by key rather than index + 2.5 pts Keys are unique + 2.5 pts Dictionaries are unordered + 1 pts Partially Correct / Not Blank When can you change the field of a namedtuple and not change the original object's id? Write a program to demonstrate. + 4 pts Answer: when the field being changed is a mutable object + 4 pts Example: nt = namedtuple('nt','immutable mutable') e = nt('s',[0]) d(1) Why is it good advice to use parentheses with Boolean expressions? Give an example where it is necessary. Boolean Expressions + 4 pts override operator precedence + 4 pts For readability of a very long and unreadable boolean expression + 4 pts Example with both "and" and "or" operators where parentheses are used to increase the precedence of the "or" operator + 2.5 pts Provided an example but not very compelling + 1 pts Not blank, but incorrect statements Why are the relational operators called "relational"? Relational Operators + 8 pts Compare two values to determine how they relate to one another (, , =, =, ==, !=) + 8 pts Makes a binary statement ranking two values + 4 pts Partially correct based on above criteria + 1 pts Not blank, but incorrect statements Explain the differences between positive and negative indexing in Python. Positive vs Negative Indexing + 0 pts Blank + 5 pts Correct + 2.5 pts Start Index: positive uses '0', negative is -1 + 2.5 pts Incrementing: positive use +1, negative uses -1 + 2.5 pts Last Index: positive = len(lst)-1, negative = -len(lst) + 1 pts Partial Credit: not blank What is the main difference between looping-by-value and looping-by-index(as discussed during lecture)? Using code, give an example to describe your answer. Difference: Loop-By-Value 4 pts 2.1 Difference + 2 pts DIFFERENCE: Looping-by-Index allows direct access to containers original contents to be modified. + 1 pts Not the main difference but a valid difference + 0 pts Incorrect