Python OOPE Exam

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🏃‍♂️ Matrix Walk Function Let’s design a Python function that follows three special matrix paths — “L”, “Z”, and “O” shapes — and collects the matrix elements accordingly! 🚀 🧑‍💻 Function Definition def matrix_walk(matrix, path): n = len(matrix) result = [] if path == "L": # Down the first column for i in range(n): result.append(matrix[i][0]) # Across the bottom row, excluding first element for j in range(1, n): result.append(matrix[n-1][j]) return result elif path == "Z": # Top row for j in range(n): result.append(matrix[0][j]) # Diagonal except first and last row for i in range(1, n-1): result.append(matrix[i][n-i-1]) # Bottom row for j in range(n): result.append(matrix[n-1][j]) return result elif path == "O": # Top row for j in range(n): result.append(matrix[0][j]) # Right column (excluding top and bottom) for i in range(1, n-1): result.append(matrix[i][n-1]) # Bottom row (reverse, excluding last element) for j in range(n-1, -1, -1): result.append(matrix[n-1][j]) # Left column (reverse, excluding top and bottom) for i in range(n-2, 0, -1): result.append(matrix[i][0]) return result else: return [] 🔍 Step-by-Step Explanation 1. L-Shape (“L”) Walk down the first column (leftmost). Then walk right along the bottom row (skipping the already-added first element). 2. Z-Shape (“Z”) Walk across the top row (left to right). Walk diagonally from the top-right to bottom-left, excluding corners. Walk across the bottom row (left to right). 3. O-Shape (“O”) Walk around the outside (clockwise): Top row (left to right), Right column (top to bottom, skipping corners), Bottom row (right to left), Left column (bottom to top, skipping corners). 🧪 Practice Questions with Solutions Example Matrix matrix = [ [1, 2, 3], [4, 5, 6], [7, 8, 9] ] Practice 1: L-Shape print(matrix_walk(matrix, "L")) # Output: [1, 4, 7, 8, 9] Practice 2: Z-Shape print(matrix_walk(matrix, "Z")) # Output: [1, 2, 3, 5, 7, 8, 9] Practice 3: O-Shape print(matrix_walk(matrix, "O")) # Output: [1, 2, 3, 6, 9, 8, 7, 4] ✨ Key Points The function traverses only as per the specified path — “L”, “Z”, or “O”. For unknown paths, returns an empty list. Works for any square matrix of size 1 or more. Happy Matrix Walking! 🟦🟩🟨🟥

📝 Filter Words by Custom Criteria Below is the requested function to filter a list of words based on one of four criteria: continuous, vowel_rich, consonant_rich, or sorted. Words are checked case-insensitively, and helper functions are included for each criteria. def filter_words(words, criteria): """ Filters a list of words based on the given criteria. Args: words (list of str): Input list of words. criteria (str): One of 'continuous', 'vowel_rich', 'consonant_rich', 'sorted'. Returns: list or None: Filtered list based on criteria, or None if invalid. Criteria: • 'continuous': words ending with 'ing' (case-insensitive) • 'vowel_rich': words with more than 5 vowels • 'consonant_rich': words with more than 5 consonants • 'sorted': words whose letters are in ascending order (case-insensitive) """ def is_continuous(word): return word.lower().endswith('ing') def count_vowels(word): return sum(1 for ch in word.lower() if ch in "aeiou") def count_consonants(word): return sum(1 for ch in word.lower() if ch.isalpha() and ch not in "aeiou") def is_sorted(word): letters = [ch.lower() for ch in word if ch.isalpha()] return letters == sorted(letters) if criteria == 'continuous': return [w for w in words if is_continuous(w)] elif criteria == 'vowel_rich': return [w for w in words if count_vowels(w) > 5] elif criteria == 'consonant_rich': return [w for w in words if count_consonants(w) > 5] elif criteria == 'sorted': return [w for w in words if is_sorted(w)] else: return None ✨ Step-by-Step Explanation Helper Functions: is_continuous: Checks if the word ends with “ing” (case-insensitive). count_vowels: Counts vowels (a, e, i, o, u). count_consonants: Counts consonants (alphabetic letters that are not vowels). is_sorted: Checks if the letters of the word are in ascending order. Criteria Check: The function checks the criteria argument and applies the relevant helper. If an unknown criteria is given, returns None. 🧪 Practice Questions Try calling the function on the following list:

🔄 Sum and Absolute Difference Alternately Let’s solve the problem step by step and make the code easy-to-follow with emojis, practice questions, and explanations! 🚀 📝 Full Python Code n = int(input()) for i in range(n): line = input().strip() # Split by comma and convert to integers a, b = map(int, line.split(',')) if i % 2 == 0: # Odd-numbered pair (1-based): print sum print(a + b) else: # Even-numbered pair (1-based): print absolute difference print(abs(a - b)) 🔍 Step-by-Step Explanation Read the number of pairs: The first input line is the integer n. Process each pair: For every line, read two comma-separated integers. Odd pair (1st, 3rd, 5th…): Print their sum. Even pair (2nd, 4th, 6th…): Print the absolute difference. Print the results one per line. 🧪 Practice Questions (with Solutions!) Practice 1 Input:

🧮 Function: is_positive_odd_or_negative_even Let’s build a Python function that checks if a number is either a positive odd or a negative even. 🎯 🚩 Function Definition def is_positive_odd_or_negative_even(n): # Check for positive odd OR negative even return (n > 0 and n % 2 == 1) or (n < 0 and n % 2 == 0) 📝 Step-by-Step Explanation Positive Odd Number: Condition: n > 0 and n % 2 == 1 Checks if the number is positive AND odd. Negative Even Number: Condition: n < 0 and n % 2 == 0 Checks if the number is negative AND even. Logical OR: The function returns True if any one of the above conditions is met. 🧪 Practice Questions Practice 1 print(is_positive_odd_or_negative_even(7)) # _______ 7 is positive and odd. Output: True Practice 2 print(is_positive_odd_or_negative_even(-4)) # _______ -4 is negative and even. Output: True Practice 3 print(is_positive_odd_or_negative_even(-3)) # _______ -3 is negative and odd. Output: False Practice 4 print(is_positive_odd_or_negative_even(8)) # _______ 8 is positive and even. Output: False Practice 5 print(is_positive_odd_or_negative_even(0)) # _______ 0 is neither positive nor negative (and it’s even). Output: False ✨ Key Points Odd number: Remainder when divided by 2 is 1 (n % 2 == 1). Even number: Remainder when divided by 2 is 0 (n % 2 == 0). Positive Odd or Negative Even: Only one of these is needed for True. Zero case: 0 is not positive or negative, so always returns False. Happy Coding! 🚀

✨ Print “X” Pattern Program Let’s write a Python program that prints an “X” shaped pattern using backslashes (\), forward slashes (/), and a lowercase x in the center! 😃 📋 Problem Description Input: An integer n (n >= 0) Output: An “X” shape with a center "x" and n identical rows above and below, built with slashes. No extra spaces to the right of the pattern. 🧑‍💻 Full Python Code n = int(input()) # Print the top part for i in range(n): # i spaces, then '\', then (2*n - 2*i - 1) spaces, then '/' left_spaces = ' ' * i middle_spaces = ' ' * (2 * n - 2 * i - 1) print(left_spaces + '\\' + middle_spaces + '/') # Print the central x print(' ' * n + 'x') # Print the bottom part (mirror of above) for i in range(n-1, -1, -1): left_spaces = ' ' * i middle_spaces = ' ' * (2 * n - 2 * i - 1) print(left_spaces + '/' + middle_spaces + '\\') 🔍 Step-by-Step Explanation Top Rows: For each row i from 0 to n-1: Print i spaces. Print a backslash (\). Print (2*n - 2*i - 1) spaces (between slashes). Print a forward slash (/). Central Row: Print n spaces, then the character 'x'. Bottom Rows: Repeat in reverse for i from n-1 to 0: Print i spaces. Print a forward slash (/). Print (2*n - 2*i - 1) spaces. Print a backslash (\). No trailing spaces are added to the right of the pattern. 🧪 Practice Examples Example 1 Input:

🗓️ mm_dd_yy_to_yy_dd_mm Function Implementation Here’s how you can implement the mm_dd_yy_to_yy_dd_mm function to convert a date string from the format mm-dd-yy to yy-dd-mm. def mm_dd_yy_to_yy_dd_mm(date: str) -> str: """ Convert a date string from the format mm-dd-yy to yy-dd-mm. Args: date (str): The date in the format "mm-dd-yy". Returns: str: The date in the format "yy-dd-mm". Example: >>> mm_dd_yy_to_yy_dd_mm("12-25-21") "21-25-12" """ mm, dd, yy = date.split('-') return f"{yy}-{dd}-{mm}" 🐍 Step-by-Step Explanation Split the String: The split('-') method divides the input string into three parts: "mm", "dd", and "yy". Unpack and Rearrange: Assign these parts to mm, dd, and yy. Then, use an f-string to rearrange them into yy-dd-mm. Return the Result: The function returns the reformatted date string. 💡 Example Usage Input: "12-25-21" Output: "21-25-12" print(mm_dd_yy_to_yy_dd_mm("12-25-21")) # Output: 21-25-12 📚 Practice Questions What will mm_dd_yy_to_yy_dd_mm("04-01-99") return? Try mm_dd_yy_to_yy_dd_mm("11-30-00") What if the input is "07-04-76"? ✅ Solutions "99-01-04" "00-30-11" "76-04-07" 🚩 Note If the input is not in the expected "mm-dd-yy" format (for example, missing dashes or incorrect number of components), the function will raise a ValueError.