Handling specific exceptions in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to catch a ZeroDivisionError exception.

Python

try:
    result = 10 / 0
except [1]:
    print("Cannot divide by zero!")

Drag options to blanks, or click blank then click option'

AZeroDivisionError

BTypeError

CValueError

DIndexError

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong exception type like ValueError or TypeError.

Not catching the exception at all.

The ZeroDivisionError is raised when division by zero occurs. Catching it allows handling this specific error.

2fill in blank

medium

Complete the code to catch a FileNotFoundError when opening a file.

Python

try:
    with open('missing.txt') as f:
        content = f.read()
except [1]:
    print("File not found.")

Drag options to blanks, or click blank then click option'

AIOError

BFileNotFoundError

COSError

DValueError

Attempts:

3 left

💡 Hint

Common Mistakes

Using IOError which is more general.

Catching the wrong exception like ValueError.

FileNotFoundError is raised when trying to open a file that does not exist.

3fill in blank

hard

Fix the error in the except clause to catch the correct exception for invalid integer conversion.

Python

try:
    number = int('abc')
except [1]:
    print("Invalid integer!")

Drag options to blanks, or click blank then click option'

AValueError

BTypeError

CNameError

DZeroDivisionError

Attempts:

3 left

💡 Hint

Common Mistakes

Using TypeError which is for wrong data types, not invalid values.

Using ZeroDivisionError which is unrelated.

Converting a non-numeric string to int raises a ValueError.

4fill in blank

hard

Fill both blanks to catch a KeyError and print a custom message.

Python

my_dict = {'a': 1}
try:
    value = my_dict[[1]]
except [2]:
    print("Key not found in dictionary.")

Drag options to blanks, or click blank then click option'

A'b'

B'a'

CKeyError

DIndexError

Attempts:

3 left

💡 Hint

Common Mistakes

Using a key that exists, so no exception is raised.

Catching the wrong exception like IndexError.

Accessing a missing key 'b' raises KeyError, which we catch to print a message.

5fill in blank

hard

Fill all three blanks to catch a TypeError when adding incompatible types and print a message.

Python

try:
    result = [1] + [2]
except [3]:
    print("Cannot add these types!")

Drag options to blanks, or click blank then click option'

A5

B'hello'

CTypeError

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Adding two numbers which does not raise an error.

Catching the wrong exception like ValueError.

Adding an integer (5) and a string ('hello') raises a TypeError, which we catch.

Practice

1. What is the main purpose of using try-except blocks in Python?

easy

A. To catch and handle specific errors so the program doesn't crash

B. To speed up the program execution

C. To write comments inside the code

D. To create new functions automatically

Solution

1. Step 1: Understand the role of try-except

   The try-except block is used to catch errors that happen during program execution.

2. Step 2: Identify the benefit of catching errors

   By catching errors, the program can handle them gracefully and continue running instead of crashing.

3. Final Answer:

   To catch and handle specific errors so the program doesn't crash -> Option A

4. Quick Check:

   try-except = catch errors [OK]

Hint: Try-except blocks catch errors to avoid crashes [OK]

Common Mistakes:

• Thinking try-except speeds up code
• Confusing try-except with comments
• Believing try-except creates functions

2. Which of the following is the correct syntax to catch a ZeroDivisionError in Python?

easy

A. try:
x = 1/0
except:
print('Error')

B. try:
x = 1/0
catch ZeroDivisionError:
print('Cannot divide by zero')

C. try:
x = 1/0
except ZeroDivisionError:
print('Cannot divide by zero')

D. try:
x = 1/0
except ZeroDivision:
print('Cannot divide by zero')

Solution

1. Step 1: Check the correct keyword for catching exceptions

   Python uses except to catch exceptions, not catch.

2. Step 2: Verify the exception name spelling

   The correct exception name is ZeroDivisionError, not ZeroDivision.

3. Final Answer:

   try: x = 1/0 except ZeroDivisionError: print('Cannot divide by zero') -> Option C

4. Quick Check:

   Use except + exact exception name [OK]

Hint: Use except with exact exception name to catch errors [OK]

Common Mistakes:

• Using 'catch' instead of 'except'
• Misspelling exception names
• Using generic except without specifying error

3. What will be the output of this code?

try:
    num = int('abc')
except ValueError:
    print('Value error caught')
except TypeError:
    print('Type error caught')

medium

A. Value error caught

B. Type error caught

C. No output

D. Program crashes with ValueError

Solution

1. Step 1: Identify the error raised by int('abc')

   Trying to convert 'abc' to int raises a ValueError.

2. Step 2: Match the error with except blocks

   The ValueError is caught by the first except block, so it prints 'Value error caught'.

3. Final Answer:

   Value error caught -> Option A

4. Quick Check:

   int('abc') = ValueError caught [OK]

Hint: Match error type to except block to find output [OK]

Common Mistakes:

• Confusing ValueError with TypeError
• Thinking program crashes without except
• Assuming no output if error caught

4. Find the error in this code and choose the correct fix:

try:
    print(10 / 0)
except ZeroDivisionError, e:
    print('Error:', e)

medium

A. Use except ZeroDivisionError(e):

B. Change except line to: except ZeroDivisionError as e:

C. Change print to print('Error') only

D. Remove the except block completely

Solution

1. Step 1: Identify the syntax error in except clause

   Python 3 requires 'as' to assign exception to a variable, not a comma.

2. Step 2: Correct the except syntax

   Replace except ZeroDivisionError, e: with except ZeroDivisionError as e:.

3. Final Answer:

   Change except line to: except ZeroDivisionError as e: -> Option B

4. Quick Check:

   Use 'as' to assign exception variable [OK]

Hint: Use 'except Exception as e:' syntax in Python 3 [OK]

Common Mistakes:

• Using comma instead of 'as' in except
• Removing except block causing crash
• Wrong parentheses in except clause

5. You want to handle both KeyError and IndexError in the same block. Which is the best way to write the except clause?

hard

A. except KeyError, IndexError:
print('Error caught')

B. except KeyError or IndexError:
print('Error caught')

C. except KeyError and IndexError:
print('Error caught')

D. except (KeyError, IndexError):
print('Error caught')

Solution

1. Step 1: Understand how to catch multiple exceptions

   Python requires a tuple of exceptions inside parentheses to catch multiple exceptions in one block.

2. Step 2: Identify correct tuple syntax

   The correct syntax is except (KeyError, IndexError): to catch both exceptions.

3. Final Answer:

   except (KeyError, IndexError): print('Error caught') -> Option D

4. Quick Check:

   Use tuple in except to catch multiple exceptions [OK]

Hint: Use except (Error1, Error2): to catch multiple exceptions [OK]

Common Mistakes:

• Using 'or' or 'and' instead of tuple
• Using comma without parentheses
• Trying to catch exceptions separately without blocks