Midterm Study Guide Fall 2024.docx

CS121 Midterm Study Guide Midterm exam is composed of writing test and programming test. Writing test is close-book while programming test is open-book. The whole test should be finished within 2 hours with one sitting. You can bring in a cheating sheet using both sides. **Chapter 1 Introduction**...

CS121 Midterm Study Guide Midterm exam is composed of writing test and programming test. Writing test is close-book while programming test is open-book. The whole test should be finished within 2 hours with one sitting. You can bring in a cheating sheet using both sides. **Chapter 1 Introduction** Review Zybook 1.2, 1.3, 1.4, and 1.6. Key concepts are: - Python interpreter - Comments, \# - Input/output functions - Type of program errors: syntax errors, runtime errors, and logic errors - Understand the concepts of processors, memory, compilers/interpreters, machine instructions, and high-level languages. Compilers/interpreters are programs that translate high-level language programs to executable programs. **Chapter 2 Variables and Expressions** Review lecture PPTs of chapter 2, and Zybook 2.1 - 2.10. Key concepts: - Variables and assignment operator = - Rules to name Python identifiers: letters, digits, and \_ - What are objects, name binding, and properties of objects - Floating-point numbers, what is an overflow, how to control decimal places - Unicode for character representation, ord() and chr() functions - Escape sequences - Arithmetic expressions, and precedence rules of arithmetic operators - Division, floor division, modulo - Shorthand operators: +=, /=, \*=, -= - Math module, import statement **Chapter 3 Types** Review PPTs and Zybook 3.1---3.9. Key concepts: - String basics: index for string characters starts from 0, strings are immutable, string concatenation (+). str = 'Monday', str\[0\] returns 'M' - List basics: index for list elements starts from 0; lists are mutable; syntax for list definition: student\_names = \['Jim', 'Peter', 'Katie'\] student\_names\[1\] returns 'Peter' Functions that manipulate a list: list.append(value), list.pop(i), list.remove(v) Pay attention to the different argument meanings of the above functions. - Tuple basics: index for tuple elements starts from 0; tuples are immutable; syntax for tuple definition uses (), not \[\]: student\_names = ('Jim', 'Peter', 'Katie') student\_names\[1\] returns 'Peter' Namedtuple module can be imported to define a new simple data type that consists of multiple attributes. Check the Car example. - Set basics: No index for set elements, since a set is unordered. sets are mutable; set elements are unique; syntax for set definition: nums = set ( \[1, 2, 3\] ), or nums = {1, 2, 3} create the same set. Set manipulation functions: add, remove, pop, clear, update, len (len function is available for all sequence types) Between-set operations: intersection, union, difference, symmetric\_difference - Dictionary basics: describing the associative relationships between **key**s and **value**s. No index for dictionary elements; mutable; syntax for dictionary: prices = {\'apples\':1.99,\'oranges\':0.99, \'banana\':0.49} print(prices\[\'apples\'\]) How to add a new entry, modify existing entries, and remove entries. - Type conversions: implicit and explicit (int(), float(), str()) - Binary number and decimal number conversion - String formatting: print(f'...{var: X}...') **Chapter 4 Branching** Review the lecture PPTs and Zybook 4.1---4.12. PPT Chap04\_1 and Chapt04\_2: - If statement, if-else statement, multi-branch if-else statement, nested if-else statement - Detecting ranges: continuous range and range with gaps - Relational operators and logical operators - Distinct if statements vs. grouped if statements Student grade example and exact change example - How to compare different data types: int, float, strings (what is the order between strings?) - How to compare two lists/tuples? Which is bigger? - How to compare two dicts? Only equal or not, cannot decide order. PPT Chap04\_3: - Membership and identity operators (in/not in, is/is not) Example - Order of evaluation (arithmetic\>relational\>logical\>assignment) - Code blocks and indentation - Conditional expressions: exp1 if condition else exp2 **Chapter 5 Loops** Review the lecture PPTs and Zybook 5.1---5.8. - While loops and for loops - When to use which? Do you know number of iterations before entering the loop? - Infinite loops - Sentinel values: the user can enter an arbitrary number of input until a sentinel value is entered. - random module: random.randint(0,2) returns a random number in the range \[0, 2\] - range() function: return a list of integers not including the end value. - Nested loops, challenge activity 5.8.3