# %cd command_line # Note: #Above was the original code given by Microsoft. # This will work the first time, but if you re-run these cells # you may encounter errors so we changed it to... # ************** DO NOT MODIFY OR ADD ANYTHING TO THIS CODE SEGMENT *********** # ************** Click Edit> Clear All Outputs *********** # ************** This code segment must be run before attempting any of the tasks or examples in this lesson ******************** # ************** This cell is a reset cell to remove (if they exist) the parent_dir and any children or leaves # It prepares the directories and files necessary to run the examples and complete the tasks. # This cell can be run first then all others cells in this notebook can be run, then this cell can be rerun # This is the reset. It uses the import shutil (or shell utility) which you will learn later in the course import os, shutil # shutil = shell utility has an important method called rmtree() # linux does not have an equivalent command! # Navigate to `library` directory (if not already in it) current_path = os.getcwd() print(current_path) if ("content" in current_path): #JGif ("library" in current_path): nb_path = current_path.split("content")[0] # nb_path = the 1st item in the split list else: nb_path = current_path print("Changing working dir to directory above parent_dir") os.chdir(os.path.join(nb_path,"content")) current_path = os.getcwd() print("Current working directory:", current_path) if (os.path.exists('parent_dir') == True): shutil.rmtree('parent_dir') os.mkdir('parent_dir') os.chdir('parent_dir') os.mkdir('child1_dir') os.chdir('../') current_path = os.getcwd() print("Current working directory:", current_path)# %mkdir command_line %cd command_line !pwd

# [ ] Write an expression to raise a `SyntaxError` exception forr i in range(10): print(i)

# [ ] Write an expression to raise a `TypeError` exception print("Hello" + 5)

## [ ] The following program divides the elements of `lst` by a float number `x` specified by the user # Use exception handling to correct for the ALL generated exceptions # When you handle all exceptions correctly, you should see the word "Done!" in the program output # HINT: You might need to use 2 `try..except` statements # Test cases: # x = 5 # x = 6.3 # x = "number" # x = 0 lst = [8, 85.4, [55, 4], 'word', (59,), {2:43.5}] x = input("Enter a number: ") try: x = float(x) except ValueError: print(f"'{x}' is an invalid input!") for i in range(7): try: print("{} / {:.2f} = {:.2f}".format(lst[i], x, lst[i] / x)) except TypeError: print(f"{lst[i]} cannot be divided by {x}") except IndexError: print(f"lst does not have an index {i}") except ZeroDivisionError: print("You cannot divide things by 0!") print("Done!")

# [ ] The following program asks the user for a file name. # The file is then opened, the first line printed out, then closed. # Use exception handling to show the user a message confirming the file process was completed successfully # your exception handling should also deal with the cases when the file does not exist # test cases: # fname = text_file.txt (should display: File process was completed successfully) # fname = nofilehere.txt (should display: nofilehere.txt was not found) import os # ask user for a file name fname = input("Enter file name: ") # the file should be located in `parent_dir` fname = os.path.join("parent_dir", fname) # opening text_file.txt for reading try: f = open(fname, 'r') print(f.readline()) f.close() print("File process was completed successfully!") except FileNotFoundError: print(f"File {fname.split('/')[1]} not found!")

# [ ] The following program tries to read from a file opened for writing. # The program will terminate before closing the file, and the file resources will not be released. # Use exception handling with a `finally` to make sure the file is closed # Open a text file for writing f = None try: f = open("parent_dir/text_file_2.txt", 'w') except FileNotFoundError: print("File not found!") # trying to read from a file open for writing (will raise an exception) try: print(f.readline()) except Exception: print("An error occurred!") # closing the file (will not be reached if an exception was raised) finally: if f is not None: f.close() print("File closed!")

# [ ] Write a program to keep prompting the user for a number from a predefined numerical tuple `valid_nums` # Your program should raise an exception with an appropriate message if the input is not valid valid_nums = (1, 2, 8, 16, 32, 64) while True: user_input = input("Enter a number from the list:") try: if not user_input.isdigit(): raise ValueError(f"{user_input} is not a valid number!") if int(user_input) not in valid_nums: raise ValueError(f"{user_input} is not on the list!") except ValueError as error: print(error) break

# ************** DO NOT MODIFY OR ADD ANYTHING TO THIS CODE SEGMENT *********** # ************** Click Edit> Clear All Outputs *********** # ************** This code segment must be run before attempting any of the tasks or examples in this lesson ******************** # ************** This cell is a reset cell to remove (if they exist) the parent_dir and any children or leaves # It prepares the directories and files necessary to run the examples and complete the tasks. # This cell can be run first then all others cells in this notebook can be run, then this cell can be rerun # This is the reset. It uses the import shutil (or shell utility) which you will learn later in the course import os, shutil # shutil = shell utility has an important method called rmtree() # linux does not have an equivalent command! # Navigate to `library` directory (if not already in it) current_path = os.getcwd() print(current_path) if ("content" in current_path): #JGif ("library" in current_path): nb_path = current_path.split("content")[0] # nb_path = the 1st item in the split list else: nb_path = current_path print("Changing working dir to directory above parent_dir") os.chdir(os.path.join(nb_path,"content")) current_path = os.getcwd() print("Current working directory:", current_path) if (os.path.exists('parent_dir') == True): shutil.rmtree('parent_dir') os.mkdir('parent_dir') os.chdir('parent_dir') os.mkdir('child1_dir') os.chdir('../') current_path = os.getcwd() print("Current working directory:", current_path)

current_path = os.getcwd() if ("parent_dir" in current_path): nb_path = current_path.split("parent_dir")[0] else: nb_path = current_path print("Changing working dir to parent_dir") os.chdir(os.path.join(nb_path,'parent_dir')) print("Current working directory:", os.getcwd()) if('files_exercises' in os.listdir()): print('Removing "files_exercises"') shutil.rmtree('files_exercises') print('Making "files_exercises"') os.mkdir('files_exercises') print('Changing working directory to "files_exercises"') os.chdir('files_exercises') print("Current working directory:", os.getcwd()) print("Creating 100 text files") random.seed(25000) # to get the same random numbers every time the setup runs for i in range(100): file_name = str(i) + ".txt" f = open(file_name, 'w') f.write(str(random.randint(1000, 9999))) f.close() print("Creating 5 directories") for i in range(1, 6): os.mkdir("dir_"+str(i)) print("Environment setup completed!")

# ************ DO NOT MODIFY OR ADD ANYTHING TO THIS CODE CELL *********************** # ++++++++++++ This code segment must be run before attempting any of the tasks in this task 4. # It prepares the directories and files necessary to complete the tasks. import os, random, shutil # Navigate to `parent_dir` directory (if not already in it) current_path = os.getcwd() if ("parent_dir" in current_path): nb_path = current_path.split("parent_dir")[0] else: nb_path = current_path print("Changing working dir to parent_dir") os.chdir(os.path.join(nb_path,'parent_dir')) print("Current working directory:", os.getcwd()) # Remove the `files_exercises` directory (if it exists) if('files_exercises' in os.listdir()): print('Removing "files_exercises"') shutil.rmtree('files_exercises') # Create a new directory called `files_exercises` print('Making "files_exercises"') os.mkdir('files_exercises') # Change the working directory to `files_exercises` print('Changing working directory to "files_exercises"') os.chdir('files_exercises') # Display the current working directory to verify you are in the correct location print("Current working directory:", os.getcwd()) # Create 100 text files, the first line of each file is a random number in the range [1000, 9999] print("Creating 100 text files") random.seed(25000) # to get the same random numbers every time the setup runs for i in range(100): file_name = str(i) + ".txt" f = open(file_name, 'w') f.write(str(random.randint(1000, 9999))) f.close() # Create 5 directories print("Creating 5 directories") for i in range(1, 6): os.mkdir("dir_"+str(i)) print("Environment setup completed!")

# [ ] Complete the function `delete_files` so the program deletes all the files in the `files_exercises` directory # Make sure the to run the environment setup code before running your own program. import os def delete_files(to_be_deleted): """ Remove all the files listed in `to_be_deleted` and leave the directories. args: to_be_deleted: list of paths returns: None """ #TODO: Your code goes here pass # list the content of `files_exercises` print('Content of "files_exercises" before removing the files') print(os.listdir()) # Delete all files in `files_exercises` delete_files(os.listdir()) # list the content of `files_exercises` print('Content of "files_exercises" after removing the files') print(os.listdir())

# [ ] The following program is designed to remove all files in `files_exercises` that contain a number divisible by 3 on the first line. # To complete the program, you need to: # 1) complete the function `delete_files` as you did in a previous exercise # 2) iterate over all content in `file_exercises`: # 2.1) if an element in the directory is a file open it for reading using `with` statement # 2.2) read the first line in the file # 2.3) if the first line contains a number divisible by 3, add the file name to the `to_be_deleted` list # 2.4) your code should handle exception appropriately (i.e. a blank file or a file containing a string in the first line) # 3) make sure the to run the environment setup code before running your own program. # The output of your program should look like: ''' Unexpected error found in 49.txt: invalid literal for int() with base 10: '' Deleting matching files: ------------------------------ Removing 15.txt Removing 16.txt Removing 18.txt Removing 19.txt Removing 20.txt Removing 23.txt Removing 28.txt Removing 35.txt Removing 39.txt Removing 40.txt Removing 44.txt Removing 46.txt Removing 5.txt Removing 51.txt Removing 52.txt Removing 54.txt Removing 55.txt Removing 58.txt Removing 59.txt Removing 65.txt Removing 67.txt Removing 68.txt Removing 69.txt Removing 71.txt Removing 73.txt Removing 77.txt Removing 80.txt Removing 81.txt Removing 85.txt Removing 87.txt Removing 91.txt Removing 94.txt Removing 95.txt Removing 96.txt ''' import os def delete_files(to_be_deleted): """ Remove all the files listed in `to_be_deleted` and leave the directories. args: to_be_deleted: list of paths returns: None """ #TODO: Copy code from previous exercise pass # list the content of `files_exercises` print('Content of "files_exercises" before removing the files') print(os.listdir()) print(30 * "-") # clearing (49.txt) so an exception is raised below as a result of int( ) # opening a file without doing anything clears it! with open('49.txt', 'w') as file: pass to_be_deleted = [] #TODO: iterate over directory content and store file names containing numbers divisible by 3 in `to_be_deleted` list print() print("Deleting matching files:") print(30 * "-") delete_files(to_be_deleted)

# [ ] Write a program to: # 1) ask the user for a number between 1000 and 9999 # 2) test if the number matches the first line of any file in `files_directory` # 3) if a match was found, print the file name; otherwise, print no match is found # 4) your code should handle exception appropriately (i.e. a blank file or a file containing a string in the first line) # 5) you should use `with` statement for opening/closing files # 6) make sure the to run the environment setup code before running your own program. # test cases: # 3932, should print out: Match found in 74.txt : 3932 # 2177, should print out: Match found in 27.txt : 2177 # 4932, should print out: No matching files found

# [ ] The tuples `x` and `y` contain the (x, y) coordinates of 10 points. # Write a program to create a single tuple `coordinates` that contains 10 sub-tuples of the (x, y) coordinates # The final tuple should look like: # ((75, 57), (77, 6), (55, 64), (93, 36), (41, 63), (62, 53), (70, 26), (30, 71), (74, 88), (97, 66)) x = (75, 77, 55, 93, 41, 62, 70, 30, 74, 97) y = (57, 6, 64, 36, 63, 53, 26, 71, 88, 66) my_list = [] for i in range(len(x)): my_list.append((x[i], y[i])) coord_tuple = tuple(my_list) print(coord_tuple)

# [ ] Write a program to merge the two sorted tuples T1, T2 into a larger (also sorted) tuple T # Output should be: #Merged sorted tuple: #(12, 13, 15, 20, 20, 26, 30, 37, 40, 55, 60, 68, 72, 78, 81, 84, 89, 97, 97, 100) # sorted tuples T1 = (15, 20, 30, 37, 55, 60, 78, 81, 84, 100) T2 = (12, 13, 20, 26, 40, 68, 72, 89, 97, 97) full_tuple = T1 + T2 T = tuple(sorted(full_tuple)) print(T)

# [ ] Complete the function `simple_stats` so it returns: # 1) The maximum number in the tuple T # 2) The minimum number in the tuple T # 3) The average of the numbers in the tuple T def simple_stats(T): return (max(T), min(T), sum(T)/len(T)) T = (257, 462, 18, 369, 415, 994, 541, 752, 78, 895, 0, 576, 40, 552, 438, 605, 54, 296, 433, 986, 685, 651, 523, 855, 777, 437, 65, 360, 265, 858, 260, 819, 586, 358, 860, 250, 531, 7, 801, 259, 155, 376, 374, 828, 475, 62, 52, 184, 186, 283, 643, 86, 472, 267, 692, 750, 948, 683, 452, 770, 322, 492, 871, 360, 88, 883, 764, 288, 383, 411, 679, 90, 857, 802, 974, 403, 798, 990, 475, 260, 289, 438, 873, 779, 895, 939, 462, 469, 183, 520, 366, 267, 896, 732, 303, 754, 195, 949, 546, 180) # unpacking and displaying the returned values largest, smallest, average = simple_stats(T) print("Maximum number in T:", largest) print("Minimum number in T:", smallest) print("Average of numbers in T:", average)

# [ ] Complete the function `longer` to compare and return the longest of 2 tuples def longer(T1, T2): """ Return the longer of two tuples args: T1: tuple of arbitrary length T2: tuple of arbitrary length returns: T1: if T1 is longer than T2 T2: if T2 is longer or the same length as T1 """ #TODO: Your code goes here pass T1 = (98, 84, 71, 87, 54, 16, 70, 62, 1, 29, 66, 1, 74, 71, 68, 58, 65, 75, 74, 77, 94, 19, 46) T2 = (62, 30, 58, 75, 0, 61, 37, 93, 40, 33, 93, 94, 72, 27, 92, 75, 38, 70, 99, 74, 89, 8, 42, 32, 4, 60, 5) print("The longer tuple is:") print(longer(T1, T2))

# [ ] Complete the function `search` so it looks for the first instance of `num` in `T` # The function should return 2 values: # 1) Boolean value indicating if num was found or not # 2) Index of the first instance of `num` in `T` def search(T, num): """ Search T for num and return the index if found; otherwise return None. args: T: Tuple to be searched num: number to use for the search returns: found: Boolean value to indicate if the num is contained in T or not i: If num is found in T return index of the first instance of num in T; otherwise, return the value `None` """ found = num in T index = None if not found else T.index(num) return (num in T, index) T = (257, 462, 18, 369, 415, 994, 541, 752, 78, 895, 0, 576, 40, 552, 438, 605, 54, 296, 433, 986, 685, 651, 523, 855, 777, 437, 65, 360, 265, 858, 260, 819, 586, 358, 860, 250, 531, 7, 801, 259, 155, 376, 374, 828, 475, 62, 52, 184, 186, 283, 643, 86, 472, 267, 692, 750, 948, 683, 452, 770, 322, 492, 871, 360, 88, 883, 764, 288, 383, 411, 679, 90, 857, 802, 974, 403, 798, 990, 475, 260, 289, 438, 873, 779, 895, 939, 462, 469, 183, 520, 366, 267, 896, 732, 303, 754, 195, 949, 546, 180) x = int(input("Enter a number to search for in T: ")) # unpacking returned tuple found, i = search(T, x) if found: print("First instance found at index {:}".format(i)) else: print("{} was not found in T".format(x))

# [ ] Complete the functions `search` and `split` to slice a tuple `T` around a number `num` # The function should use the `search` function you developed in a previous exercise to find its index in `T` # If `num` is in T, you discard it and return two tuples: # 1) from the beginning of T till index of num # 2) from index+1 of num till the end of T # If `num` is not in T, you return: # 1) The whole Tuple # 2) The `None` value # Example input/output using T = (15, 20, 30, 37, 55, 60, 78, 81, 84, 100): #Enter a number around which you want to split T: 55 #T1 = (15, 20, 30, 37) #T2 = (60, 78, 81, 84, 100) #Enter a number to search for in T: 400 #T1 = (15, 20, 30, 37, 55, 60, 78, 81, 84, 100) #T2 = None def search(T, num): """ Search T for num and return the index if found; otherwise return None. args: T: Tuple to be searched num: number to use for the search returns: found: Boolean value to indicate if the num is contained in T or not i: If num is found in T return index of the first instance of num in T; otherwise, return the value `None` """ found = num in T index = None if not found else T.index(num) return (found, index) def split(T, num): """ Split the tuple T around num (num should be discarded). args: T: Tuple to be searched num: number to use for the split returns: T1: The first half of the tuple, from the beginning till num ( excluded). If num is not in T, T1 should be the whole tuple T T2: The second half of the tuple, from num (excluded) till the end. If num is not in T, T2 should be the value `None` """ found, index = search(T, num) T1 = T if index is None else T[:index] T2 = None if index is None else T[index+1:] return (T1, T2) T = (15, 20, 30, 37, 55, 60, 78, 81, 84, 100) x = int(input("Enter a number around which you want to split T: ")) # unpacking returned tuple T1, T2 = split(T, x) print("T1 =", T1) print("T2 =", T2)

# [ ] The `data` list contains grocery store inventory information, the list is organized into sublists where each of # the sublists contains: [UPC, Description, Unit Price, Quantity in Stock] # Use the `data` list to create an inventory dictionary with the UPC as keys and lists containing [Description, Item Price, Quantity in Stock] as values: # UPC (as keys): [Description, Unit Price, Quantity in Stock] (as values) # NOTE: UPC is short for (Universal Product Code), which is the number found under a barcode and identify different products in a store # The created dictionary should look like: # {847502: ['APPLES 1LB', 1.99, 50], 847283: ['OLIVE OIL', 10.99, 100], 839529: ['TOMATOS 1LB', 1.29, 25], 483946: ['MILK 1/2G', 3.45, 35], 493402: ['FLOUR 5LB', 2.99, 40], 485034: ['BELL PEPPERS 1LB', 1.35, 28], 828391: ['WHITE TUNA', 1.69, 100], 449023: ['CHEESE 1/2LB', 4.99, 15]} data = [[847502, "APPLES 1LB", 1.99, 50], [847283, "OLIVE OIL", 10.99, 100], [839529, "TOMATOS 1LB", 1.29, 25], [483946, "MILK 1/2G", 3.45, 35], [493402, "FLOUR 5LB", 2.99, 40], [485034, "BELL PEPPERS 1LB", 1.35, 28], [828391, "WHITE TUNA", 1.69, 100], [449023, "CHEESE 1/2LB", 4.99, 15]] #TODO: Your code goes here grocery_dict = {} for item in data: grocery_dict[item[0]] = [item[1], item[2], item[3]] print(grocery_dict)

# [ ] Use the `inventory` dictionary in a program that asks the user for a UPC number then prints the item information # Your program should print an appropriate message if the UPC is not in the inventory # test cases: # input 1: 847283 # output: ''' UPC | Description | Unit Price | Quantity ------------------------------------------------------- 847283 | OLIVE OIL | 10.99 | 100.00 ''' # input 2: 340344 # output: No inventory found for 340344 inventory = {847502: ['APPLES 1LB', 1.99, 50], 847283: ['OLIVE OIL', 10.99, 100], 839529: ['TOMATOS 1LB', 1.29, 25], 483946: ['MILK 1/2G', 3.45, 35], 493402: ['FLOUR 5LB', 2.99, 40], 485034: ['BELL PEPPERS 1LB', 1.35, 28], 828391: ['WHITE TUNA', 1.69, 100], 449023: ['CHEESE 1/2LB', 4.99, 15]} #TODO: Your code goes here num = int(input("Enter UPC:")) if num not in inventory.keys(): print(f"{num} is not in the inventory!") else: item = inventory[num] print(f"{'UPC':^10s}| {'Description':<20s}|{'Unit Price':^15s}|{'Quantity':^15s}") print("-"*61) print(f"{num:<10d}| {item[0]:<20s}|{item[1]:>14.2f} |{item[2]:>12.2f}")

# [ ] Use the `inventory` dictionary in a program that asks the user for a UPC number, description, unit price, # quantity in stock. # If the item already exists in the inventory, the information is updated, # and your program should display a message that it is updating the entry. # If the item does NOT exists in the inventory, a new dictionary entry is created, # and your program should display a message that it is creating a new entry. # Use try/except in the program. # test cases # For an existing item ''' Enter UPC number: 839529 Enter item description: TOMATOS 1LB Enter unit price: 1.55 Enter item quantity: 21 Existing item, updating: ['TOMATOS 1LB', 1.29, 25] UPC | Description | Unit Price | Quantity ------------------------------------------------------- 839529 | TOMATOS 1LB | 1.55 | 21.00 ''' # For a new item ''' Enter UPC number: 29430 Enter item description: ORANGE 1LB Enter unit price: 0.99 Enter item quantity: 40 New item, creating ORANGE 1LB UPC | Description | Unit Price | Quantity ------------------------------------------------------- 29430 | ORANGE 1LB | 0.99 | 40.00 ''' inventory = {847502: ['APPLES 1LB', 1.99, 50], 847283: ['OLIVE OIL', 10.99, 100], 839529: ['TOMATOS 1LB', 1.29, 25], 483946: ['MILK 1/2G', 3.45, 35], 493402: ['FLOUR 5LB', 2.99, 40], 485034: ['BELL PEPPERS 1LB', 1.35, 28], 828391: ['WHITE TUNA', 1.69, 100], 449023: ['CHEESE 1/2LB', 4.99, 15]} #TODO: Your code goes here upc = int(input("Enter UPC number:")) desc = input("Enter item description:") price = float(input("Enter unit price:")) quantity = int(input("Enter item quantity:")) item = [desc, price, quantity] if upc in inventory.keys(): print(f"Existing item, updating: {item}") else: print(f"New item, creating {desc}") inventory[upc] = item print(f"{'UPC':^10s}| {'Description':<20s}|{'Unit Price':^15s}|{'Quantity':^15s}") print("-"*61) print(f"{num:<10d}| {item[0]:<20s}|{item[1]:>14.2f} |{item[2]:>12.2f}")

# [ ] Write a program to display the current inventory information as follow # Note the items are sorted by UPC ''' UPC | Description | Unit Price | Quantity ------------------------------------------------------- 449023 | CHEESE 1/2LB | 4.99 | 15.00 483946 | MILK 1/2G | 3.45 | 35.00 485034 | BELL PEPPERS 1LB | 1.35 | 28.00 493402 | FLOUR 5LB | 2.99 | 40.00 828391 | WHITE TUNA | 1.69 | 100.00 839529 | TOMATOS 1LB | 1.29 | 25.00 847283 | OLIVE OIL | 10.99 | 100.00 847502 | APPLES 1LB | 1.99 | 50.00 ''' inventory = {847502: ['APPLES 1LB', 1.99, 50], 847283: ['OLIVE OIL', 10.99, 100], 839529: ['TOMATOS 1LB', 1.29, 25], 483946: ['MILK 1/2G', 3.45, 35], 493402: ['FLOUR 5LB', 2.99, 40], 485034: ['BELL PEPPERS 1LB', 1.35, 28], 828391: ['WHITE TUNA', 1.69, 100], 449023: ['CHEESE 1/2LB', 4.99, 15]} print() print("{:^7s} | {:<17s} | {:^12s} | {:^10s}".format("UPC", "Description", "Unit Price", "Quantity")) print(55 * '-') for UPC in sorted(inventory): print("{:<7d} | {:<17s} | {:>12.2f} | {:>10.2f}".format(UPC, inventory[UPC][0], inventory[UPC][1], inventory[UPC][2]))

# [ ] Write a program to calculate and display the total value and the number of items in an inventory. # The total value can by calculated by multiplying each unit price by the quantity, # then adding up the answers for all items in the inventory. inventory = {847502: ['APPLES 1LB', 1.99, 50], 847283: ['OLIVE OIL', 10.99, 100], 839529: ['TOMATOS 1LB', 1.29, 25], 483946: ['MILK 1/2G', 3.45, 35], 493402: ['FLOUR 5LB', 2.99, 40], 485034: ['BELL PEPPERS 1LB', 1.35, 28], 828391: ['WHITE TUNA', 1.69, 100], 449023: ['CHEESE 1/2LB', 4.99, 15]} total_items = 0 total_price = 0 for value in inventory.values(): total_items += value[2] total_price += value[1]*value[2] print(f"Total items = {total_items}") print(f"Total price: ${total_price:.2f}")