Day 9 - Error Handling

Author: Zemerik

Diff for: Day 9 - Error Handling/README.md

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+# Day 9: Error Handling
+
+## What You'll Learn:
+- Handling exceptions with `try/except`
+- Using `finally` for cleanup operations
+- Raising custom exceptions
+- Built-in exception types
+
+## Files:
+1. `basic_try_except.py` - Simple error catching
+2. `specific_exceptions.py` - Handling different error types
+3. `finally_usage.py` - Cleanup operations
+4. `raising_exceptions.py` - Custom error raising
+
+## Exercises:
+1. Create a number input validator that:
+   - Keeps asking for input until valid number
+   - Handles both ValueError and KeyboardInterrupt
+   - Prints "Thank you!" on successful input
+
+2. Build a file reader that:
+   - Gracefully handles missing files
+   - Shows different messages for different error types
+   - Always closes file resources

Diff for: Day 9 - Error Handling/basic_try_except.py

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+# Basic error handling
+try:
+    result = 10 / 0
+except ZeroDivisionError:
+    print("Cannot divide by zero!")
+
+# Generic exception
+try:
+    print(undefined_variable)
+except Exception as e:
+    print(f"Error occurred: {str(e)}")

Diff for: Day 9 - Error Handling/finally_usage.py

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+# Finally block example
+try:
+    file = open("data.txt", "r")
+    content = file.read()
+    print(content)
+except FileNotFoundError:
+    print("File doesn't exist")
+finally:
+    file.close() if 'file' in locals() else None
+    print("Cleanup complete")

Diff for: Day 9 - Error Handling/raising_exceptions.py

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+# Raising exceptions
+def validate_age(age):
+    if age < 0:
+        raise ValueError("Age cannot be negative")
+    if age > 120:
+        raise ValueError("Unrealistic age")
+        
+try:
+    validate_age(-5)
+except ValueError as e:
+    print(f"Invalid age: {e}")
+
+# Custom exception
+class InvalidEmailError(Exception):
+    pass
+
+def validate_email(email):
+    if "@" not in email:
+        raise InvalidEmailError("Missing @ symbol")

Diff for: Day 9 - Error Handling/specific_exceptions.py

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+# Handling specific exceptions
+try:
+    file = open("missing.txt", "r")
+    value = int("abc")
+except FileNotFoundError:
+    print("File not found!")
+except ValueError:
+    print("Invalid conversion to integer")