How Python executes code - Practice Exercises

Challenge - 5 Problems

❓ Predict Output

intermediate

Understanding Python Execution Order

What is the output of this Python code snippet?

Python

def greet():
    print("Hello")

print("Start")
greet()
print("End")

A Hello\nStart\nEnd

B Start\nHello\nEnd

C Start\nEnd\nHello

D Hello\nEnd\nStart

💡 Hint

Think about the order in which functions are called and print statements run.

Python runs code line by line. First it prints "Start", then calls greet() which prints "Hello", then prints "End".

❓ Predict Output

intermediate

Variable Scope in Python Execution

What will be the output of this code?

Python

x = 5
def change():
    x = 10
change()
print(x)

A 5

B 10

C None

D Error

💡 Hint

Consider where the variable x is changed and where it is printed.

The change() function creates a new local variable x. The global x remains 5, so print(x) outputs 5.

❓ Predict Output

advanced

Order of Execution with List Comprehensions

What is the output of this code?

Python

result = [x**2 for x in range(3)]
print(result)

A Error

B [1, 4, 9]

C [0, 1, 2]

D [0, 1, 4]

💡 Hint

Remember that range(3) produces 0,1,2 and each is squared.

The list comprehension squares each number from 0 to 2, resulting in [0, 1, 4].

❓ Predict Output

advanced

Execution Flow with Conditional Statements

What will this code print?

Python

x = 7
if x > 5:
    print("Greater")
else:
    print("Smaller")

A Error

B Smaller

C Greater

D Nothing

💡 Hint

Check the condition in the if statement carefully.

Since 7 is greater than 5, the if block runs and prints "Greater".

🧠 Conceptual

expert

Python Execution Model: What Happens First?

When Python runs a script, which step happens first?

A Python compiles the code to bytecode before running it

B Python immediately runs the code line by line without compilation

C Python converts the code to machine code directly

D Python sends the code to the operating system to execute

💡 Hint

Think about how Python prepares code before executing it.

Python first compiles the source code into bytecode, which is a lower-level, platform-independent representation. Then it runs this bytecode on the Python Virtual Machine.