sync

Python Course Materials/Week8/DKIFER_Week8_lab_exception_handling.py

@@ -0,0 +1,123 @@
+# Week 8 - Lab: Python Program
+# Assignment Value: 10 points
+# Description:
+
+#     Create a Python program that demonstrates exception handling.  
+#     Your program should include at least three custom-defined exceptions and handle them appropriately.
+#     Implement try-except blocks to handle exceptions and provide meaningful error messages.
+#     Test your program with various scenarios to ensure proper exception handling.
+
+# Instructions:
+
+#     Create a Python script named exception_handling.py. 
+#     Define three custom exceptions: CustomError1, CustomError2, and CustomError3.
+#     Implement a function divide_numbers() that takes two numbers as input and returns the result of dividing the first number by the second number.
+#         Handle the ZeroDivisionError exception. If the second number is zero, raise CustomError1.
+#     Implement a function open_file() that takes a filename as input and tries to open the file.
+#         Handle the FileNotFoundError exception. If the file does not exist, raise CustomError2.
+#     Implement a function process_data() that takes a list as input and tries to access an element at a specific index.
+#         Handle the IndexError exception. If the index is out of range, raise CustomError3.
+#     In the main part of your script, demonstrate the usage of all the implemented functions by invoking them and handling exceptions appropriately.  
+#     Take a screenshot of Thonny showing both the code and output at the end of the exercise.
+#     Upload the screenshot. 
+
+# Directions for submitting your written assignment as an attachment:
+
+#     When you have completed the assignment, save the file on your computer with your name as part of the file name, for example, a_student_assignment1.docx [using your first initial and last name]
+#     Click on the title of the assignment above.
+#     Click on "Upload Files".
+#     Click on the "Browse Local Files" button to attach your file to this assignment.
+#     Once you have attached your file, click on the "Submit" button to send your file to your instructor.
+
+# Note: This assignment is due 11:59 PM ET, Sunday of Week 8.
+
+import os
+
+def divide_numbers(num1, num2):
+    try:
+        print(f"Dividing numbers {num1} / {num2}")
+        if num2 == 0:
+            raise CustomError1
+        return num1 / num2
+    except CustomError1:
+        print("CustomError1: Cannot divide by zero.")
+
+def open_file(input_file):
+    try:
+        print(f"Trying to open the {input_file}")
+        with open(input_file, 'r') as f:
+            print(f"{input_file} has been opened successfully.")
+            pass
+    except FileNotFoundError:
+        raise CustomError2
+
+def process_data(data, index):
+    try:
+        print(f"Trying to return the data for each index.")
+        return data[index]
+    
+    except IndexError:
+        raise CustomError3
+    
+class CustomError1(Exception):
+    pass
+
+class CustomError2(Exception):
+    pass
+
+class CustomError3(Exception):
+    pass
+
+def __main__():
+    script_directory = os.path.dirname(os.path.abspath(__file__)) # get the directory of the script
+    input_file = os.path.join(script_directory, "input.txt") #had to use os.path.join to get the correct path. Wasn't working with just the file name
+    fail_input_file = os.path.join(script_directory, "doesnotexist.txt")
+    try:
+        print("\n\n----------Division Function-------------")
+        print("----------------------------------------")
+        print(f"Failure case: {divide_numbers(10, 0)}")
+        print(f"Success case: {divide_numbers(100, 10)}")
+        
+    except CustomError1:
+        print("CustomError1 handled.")
+
+    print("----------End Division Function---------\n\n")
+
+
+    try:
+        print("---------Open File Function-------------")
+        print("----------------------------------------")
+        print(f"Success Case: Trying to open {input_file}")
+        open_file(input_file)
+        
+        print(f"Fail Case: Trying to open {fail_input_file}")
+        open_file(fail_input_file)
+    
+    except CustomError2:
+        print("CustomError2 handled.")
+
+    print("---------End Open File Function---------\n\n")
+
+
+    try:
+        print("-------Process List Input Function------")
+        print("----------------------------------------")
+        print(f"Failure case: {process_data([1, 2, 3], 3)}")
+        print(process_data([1, 2, 3], 2))
+        
+    except CustomError3:
+        print("CustomError3 handled.")
+
+    try:
+        print("-------Process List Input Function------")
+        print("----------------------------------------")
+        print(f"Success case: {process_data([1, 2, 3], 2)}")
+        
+    except CustomError3:
+        print("CustomError3 handled.")
+   
+    print("----End Process List Input Function-----\n\n")
+
+if __name__ == "__main__":
+    
+    __main__()