Python Garbage Collection

Question 1

What is the primary purpose of a garbage collector in Python?

Answer 1

To automatically manage memory by reclaiming memory occupied by objects that are no longer in use.

Question 2

True or False: Python uses reference counting as its primary garbage collection mechanism.

Answer 2

True

Question 3

Fill in the blank: The process of identifying and freeing memory occupied by objects that are no longer referenced is called _______.

Answer 3

garbage collection

Question 4

What is reference counting?

Answer 4

A technique where each object keeps track of the number of references pointing to it.

Question 5

What happens when an object’s reference count reaches zero?

Answer 5

The memory occupied by the object is reclaimed by the garbage collector.

Question 6

Which module in Python provides an interface to the garbage collection facilities?

Answer 6

The ‘gc’ module.

Question 7

True or False: Cyclic references can be handled by Python’s garbage collector.

Answer 7

True

Question 8

What is a cyclic reference?

Answer 8

A situation where two or more objects reference each other, creating a cycle that prevents reference counting from reaching zero.

Question 9

How does Python’s garbage collector handle cyclic references?

Answer 9

It uses a technique called cycle detection to identify and collect objects involved in cycles.

Question 10

What is the function used to manually trigger garbage collection in Python?

Answer 10

gc.collect()

Question 11

Fill in the blank: The default garbage collection strategy in Python is based on _______ and _______.

Answer 11

reference counting; cycle detection

Question 12

What is the ‘gc.set_debug()’ function used for?

Answer 12

To enable debugging options for the garbage collector.

Question 13

What does the ‘gc.get_objects()’ function return?

Answer 13

A list of all objects tracked by the garbage collector.

Question 14

True or False: Garbage collection can lead to performance issues if not managed properly.

Answer 14

True

Question 15

What is the purpose of the ‘gc.collect()’ method?

Answer 15

To force a garbage collection of unreachable objects.

Question 16

What does the ‘gc.get_stats()’ function provide?

Answer 16

Statistics about the current state of the garbage collector.

Question 17

What is ‘finalization’ in the context of garbage collection?

Answer 17

The process of calling an object’s finalizer method before the object is reclaimed.

Question 18

True or False: Python’s garbage collector can be disabled.

Answer 18

True

Question 19

What is the command to disable Python’s garbage collector?

Answer 19

gc.disable()

Question 20

What is the impact of disabling the garbage collector?

Answer 20

It can lead to increased memory usage and potential memory leaks.

Question 21

What is the purpose of weak references in Python?

Answer 21

To allow the garbage collector to reclaim an object without preventing its memory from being freed.

Question 22

What module provides support for weak references?

Answer 22

The ‘weakref’ module.

Question 23

Fill in the blank: Objects created with weak references can still be _______ by the garbage collector.

Answer 23

collected

Question 24

What is a ‘weak reference’?

Answer 24

A reference to an object that does not increase its reference count.

Question 25

What is the function of 'gc.get_referrers()'?

Answer 25

To return a list of objects that refer to a given object.

Question 26

True or False: Python's garbage collector is non-deterministic.

Answer 26

True

Question 27

What is the significance of the 'gc.garbage' list?

Answer 27

It contains a list of objects that the garbage collector found to be unreachable but cannot be freed.

Question 28

What is the purpose of the '__del__' method?

Answer 28

To define a finalizer for an object that is called when the object is about to be destroyed.

Question 29

True or False: The '__del__' method is guaranteed to be called when an object is garbage collected.

Answer 29

False

Question 30

What can prevent the '__del__' method from being executed?

Answer 30

If there are circular references involving the object.

Question 31

What is the 'gc.get_count()' function used for?

Answer 31

To return the current collection counts for the garbage collector.

Question 32

Fill in the blank: The garbage collector is part of the _______ module in Python.

Answer 32

gc

Question 33

What does 'gc.collect(generation)' do?

Answer 33

It collects garbage from the specified generation.

Question 34

What are the three generations in Python's garbage collection?

Answer 34

Young, middle-aged, and old generations.

Question 35

True or False: Older objects are collected more frequently than younger objects in Python's garbage collection.

Answer 35

False

Question 36

What is the 'threshold' in Python's garbage collection?

Answer 36

The number of allocations and deallocations that trigger a collection cycle.

Question 37

How can you change the garbage collection thresholds?

Answer 37

Using the 'gc.set_stats()' method.

Question 38

What is the default garbage collection threshold for generation 0?

Answer 38

700

Question 39

True or False: Python does not allow for custom garbage collection strategies.

Answer 39

False

Question 40

What is the potential downside of relying solely on garbage collection?

Answer 40

It can lead to unpredictable performance and latency in memory management.

Question 41

What is the role of the 'gc' module in Python?

Answer 41

To provide an interface for interacting with the garbage collection process.

Question 42

Fill in the blank: The Python garbage collector uses _______ to detect cycles.

Answer 42

tracing

Question 43

What happens during a garbage collection cycle?

Answer 43

The collector identifies unreachable objects and reclaims their memory.

Question 44

What is the purpose of the 'gc.collect(generation)' function?

Answer 44

To explicitly trigger garbage collection for a specific generation.

Question 45

True or False: Memory leaks are impossible in Python due to garbage collection.

Answer 45

False