বিশ্বায়নের কোন্ মৌলিক উপাদানের প্রবাহ অপেক্ষাকৃত কম?

Question:

What will be the output of the following Python code?

def update_record(data):
    data.append(40)
    data = [100, 200]

numbers = [10, 20, 30]
update_record(numbers)
print(numbers)

Options:

    
• A) [10, 20, 30]
    
• B) [10, 20, 30, 40]
    
• C) [100, 200]
    
• D) [100, 200, 40]

Correct Answer: B

Explanation:

Python uses a mechanism known as pass-by-object-reference (or pass-by-assignment):

    
• When numbers is passed into update_record(data), the parameter data references the exact same list object in memory.
    
• The operation data.append(40) modifies the list in place. Because lists are mutable, the original list numbers now contains [10, 20, 30, 40].
    
• The subsequent assignment data = [100, 200] merely rebinds the local variable data to a new list object in memory. This reassignment does not affect the outer numbers variable.
    
• Therefore, when print(numbers) executes, it outputs the modified original list: [10, 20, 30, 40].