Built-in scope in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print the absolute value of -5 using a built-in function.

Python

print([1](-5))

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

Aabs

Bmin

Cmax

Dlen

Attempts:

3 left

💡 Hint

Common Mistakes

Using len() which is for length of collections.

Using max() or min() which compare values but don't change sign.

The abs() function returns the absolute value of a number.

2fill in blank

medium

Complete the code to convert the string '123' to an integer using a built-in function.

Python

number = [1]('123')
print(number + 1)

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

Afloat

Bstr

Cint

Dbool

Attempts:

3 left

💡 Hint

Common Mistakes

Using str() which keeps it as text.

Using float() which converts to decimal number.

Using bool() which converts to True or False.

The int() function converts a string representing a number into an integer.

3fill in blank

hard

Fix the error in the code by completing the blank with the correct built-in function to get the length of the list.

Python

my_list = [1, 2, 3, 4]
print([1](my_list))

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

Alen

Blength

Csize

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using count which is a list method but needs an argument.

Using length or size which are not built-in functions in Python.

The built-in function len() returns the number of items in a list.

4fill in blank

hard

Fill both blanks to create a dictionary with words as keys and their lengths as values, using built-in functions.

Python

words = ['apple', 'bee', 'cat']
lengths = { [1]: [2] for word in words }

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

Aword

Blen(word)

Cword.upper()

Dword.lower()

Attempts:

3 left

💡 Hint

Common Mistakes

Using word.upper() or word.lower() as values instead of lengths.

Using len without parentheses.

The dictionary comprehension uses the word as the key and len(word) as the value.

5fill in blank

hard

Fill all three blanks to create a dictionary with uppercase keys and values that are True if the length is greater than 3.

Python

words = ['dog', 'elephant', 'cat']
result = { [1]: [2] > 3 for [3] in words }

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

Aword.upper()

Blen(word)

Cword

Dword.lower()

Attempts:

3 left

💡 Hint

Common Mistakes

Using word.lower() instead of uppercase for keys.

Using word instead of len(word) for values.

Not using the loop variable word correctly.

The keys are uppercase words, the values check if length is greater than 3, and the loop variable is word.

Practice

1. Which of the following best describes the built-in scope in Python?

easy

A. It is where user-defined variables are stored.

B. It is the first place Python looks for variable names.

C. It contains names of functions and variables Python always knows.

D. It only contains names defined inside functions.

Solution

1. Step 1: Understand what built-in scope means

   Built-in scope contains names of functions and constants Python always knows, like print and len.

2. Step 2: Identify where Python looks last

   Python looks in local, then global, then built-in scope last when searching for a name.

3. Final Answer:

   It contains names of functions and variables Python always knows. -> Option C

4. Quick Check:

   Built-in scope = Python's always known names [OK]

Hint: Built-in scope has Python's default functions and constants [OK]

Common Mistakes:

• Thinking built-in scope is searched first
• Confusing built-in scope with local or global scope
• Assuming user variables are in built-in scope

2. Which of the following is the correct way to use a built-in function without causing a naming conflict?

easy

A. print('Hello, world!')

B. def print(): pass

C. len = 5

D. input = 'data'

Solution

1. Step 1: Identify correct usage of built-in functions

   Using print('Hello, world!') calls the built-in print function correctly.

2. Step 2: Recognize naming conflicts

   Defining print, len, or input as variables or functions overwrites built-ins and causes conflicts.

3. Final Answer:

   print('Hello, world!') -> Option A

4. Quick Check:

   Use built-ins directly without redefining [OK]

Hint: Avoid naming variables same as built-ins to prevent errors [OK]

Common Mistakes:

• Redefining built-in function names as variables or functions
• Calling built-ins after overwriting them
• Assuming built-ins can be safely replaced

3. What will be the output of the following code?

len = 10
print(len('hello'))

medium

A. 5

B. 10

C. NameError

D. TypeError

Solution

1. Step 1: Understand variable shadowing

   The variable len is assigned the integer 10, which hides the built-in len function.

2. Step 2: Analyze the function call

   Calling len('hello') tries to call the integer 10 as a function, causing a TypeError.

3. Final Answer:

   TypeError -> Option D

4. Quick Check:

   Overwriting built-in function causes TypeError when called [OK]

Hint: Overwriting built-ins causes errors when called as functions [OK]

Common Mistakes:

• Expecting output 5 (length of 'hello')
• Confusing variable value with function behavior
• Ignoring that built-in is overwritten

4. Find the error in this code snippet:

def input():
    return 'user input'

print(input())
print(len('abc'))

medium

A. SyntaxError due to function definition

B. No error, prints 'user input' and 3

C. Error because len is undefined

D. Error because input is redefined, blocking built-in input

Solution

1. Step 1: Check function definition and shadowing

   Defining input() shadows the built-in input, but the code calls the custom function.

2. Step 2: Verify execution flow

   print(input()) prints 'user input'; print(len('abc')) uses built-in len (unaffected) and prints 3. No errors occur.

3. Final Answer:

   No error, prints 'user input' and 3 -> Option B

4. Quick Check:

   Code executes fine despite shadowing [OK]

Hint: Avoid redefining built-in names to prevent unexpected behavior [OK]

Common Mistakes:

• Thinking redefining input causes immediate runtime error
• Assuming len is undefined or affected
• Confusing bad practice with actual syntax or runtime error

5. You want to use the built-in max function inside a function that has a local variable named max. How can you still call the built-in max function?

hard

A. Use __builtins__.max() to call the built-in function.

B. Rename the local variable to max_builtin.

C. Call max() directly; Python will use the built-in automatically.

D. Use global max inside the function.

Solution

1. Step 1: Understand local variable shadowing

   A local variable named max hides the built-in max function inside the function scope.

2. Step 2: Access built-in function explicitly

   Using __builtins__.max() calls the original built-in max function despite the local variable.

3. Final Answer:

   Use __builtins__.max() to call the built-in function. -> Option A

4. Quick Check:

   Use __builtins__ to access hidden built-ins [OK]

Hint: Use __builtins__.function() to bypass local shadowing [OK]

Common Mistakes:

• Assuming calling max() calls built-in despite local variable
• Using global keyword incorrectly
• Renaming variable without changing code