2 Different Ways to Clear Memory in Python

We will learn how to clear or delete a memory in python. There is a way to delete a memory for the unused variables, list, or array to save the memory. We will learn how to clear memory for a variable, list, and array using two different methods. The two different methods are del and gc.collect().

del and gc.collect() are the two different methods to delete the memory in python. The clear memory method is helpful to prevent the overflow of memory. We can delete that memory whenever we have an unused variable, list, or array using these two methods. It will save the memory. As efficient programmers, we need to know how to save memory. So these two methods are beneficial for the programmers. 

What is del method?

del method is useful to delete unused variables, lists, and arrays. This method is useful to save memory allocation.

Syntax

del(element)

Parameter

element: It may be a variable, list, or array that we want to delete.

Ways to Clear Memory in Python

1. How to clear a variable?

a=10
del a
print(a)

Here we have created a variable a. After that, we have deleted that variable using the del statement. This is means clearing the memory in python. Now we will try to print the variable. Let us see what the output is while we print the variable.

Output

Traceback (most recent call last):
  File "C:\Users\AppData\Local\Programs\Python\Python39\io.py", line 17, in <module>
    print(a)
NameError: name 'a' is not defined

2. How to clear a list?

lst=[10,80,60,45]
del lst
print(lst)

In the above program, we are going to clear a list using a del command. After deleting a list, we are trying to print the list whether the list is successfully created or not. While the program hits the print(list) statement, if it returns a Name error, the list is deleted successfully.

Output

Traceback (most recent call last):
  File "C:\Users\AppData\Local\Programs\Python\Python39\io.py", line 17, in <module>
    print(lst)
NameError: name 'lst' is not defined

3. How to clear an array?

import numpy as np
array=np.array([1,2,3,4])
del(array)
print(array)

Let us take an array and delete it using a del command. After deleting that, let us see the output for print(array).

Output

Traceback (most recent call last):
  File "C:\Users\AppData\Local\Programs\Python\Python39\io.py", line 22, in <module>
    print(array)
NameError: name 'array' is not defined

Must Read | How to Solve Memory Error in Python

What are the problems we will face while clear the memory in python?

We have seen a lot of examples to clear the memory by using the del method. After using this type of statement, the objects are no longer accessible for the given code. But, the objects are still there in the memory.

To solve this issue, python introduced gc.collect() method to clear the memory. Python introduced gc module in the version of python 1.5.

What is gc.collect() method?

gc.collect is a method that is useful to prevent the overflow of memory. It will delete the elements.

Clear the memory in python using gc.collect() method

1. How to clear a variable using gc.collect()?

import gc
a=10
del a
gc.collect()
print(a)

Import gc. Create a variable a is equal to 10. Delete a. Now we will check using a print statement.

Output

Traceback (most recent call last):
  File "C:\Users\AppData\Local\Programs\Python\Python39\io.py", line 28, in <module>
    print(a)
NameError: name 'a' is not defined

2. How to clear a list using gc.collect()?

import gc
lst=[1,6,3,68]
del lst
gc.collect()
print(lst)

Import gc. I am creating a list in a variable list. Now the list is deleted successfully.

Output

Traceback (most recent call last):
  File "C:\Users\AppData\Local\Programs\Python\Python39\io.py", line 28, in <module>
    print(lst)
NameError: name 'lst' is not defined

How to clear an array using gc.collect()?

import numpy as np
import gc
array=np.array([1,6,3,68])
del array
gc.collect()
print(array)

Import gc. Create an array. Make use of the del command to delete the memory created for the array.

Output

Traceback (most recent call last):
  File "C:\Users\AppData\Local\Programs\Python\Python39\io.py", line 29, in <module>
    print(array)
NameError: name 'array' is not defined

How to identify and fix memory leaks?

When the programmer forgets to delete an unused memory, then the memory will get overflow, and it causes memory leaks. Memory link will cause because of lingering large objects which are not released and reference cycles within the code.

Finding the memory leaks in python

GC module is helpful to debug the memory leaks in python. It provides the garbage collector, has a list of all objects. This module will give an idea of where the program’s memory is being used. Then the objects are filtered. GC module will identify the unused objects so that the user can delete the unused memory. This will prevent memory leaks in python.

The GC module will tell the information about how many objects are created. Still, it does not give the information about how the objects are being allocated so that it would have no use in identifying the code causing memory leaks.

Fixing memory leaks in python

Python introduced a built-in function named Tracemalloc module. This module is presented in the version of python 3.4. It is helpful for solving memory leaks in python. Tracemallc module provides block-level traces of memory allocation. This will tell where the memory was allocated.

FAQs Related to clear memory in python

Conclusion

So far, we have wholly learned about how to clear the memory in python. We have learned a lot of things in this article. These are the beneficial and necessary things to learn as a python programmer.

We hope this article is easy to understand. In case of any queries, do let us know in the comment section.