CODEWITHSUNDEEP
pythonmemory
Adit Srivastava
Adit Srivastava

Reputation: 95

Python MemoryError on large array

This is the python script that I'm trying to run:

n = 50000000000 ##50 billion 
b = [0]*n
for x in range(0,n):
    b[x] = random.randint(1,899999)

... But the output I'm getting is:

E:\python\> python sort.py
Traceback (most recent call last):
  File "E:\python\sort.py", line 8, in <module>
    b = [0]*n
MemoryError

So, what do I do now?

Upvotes: 6

Views: 13900

Answers (3)

MarcosDGF
MarcosDGF

Reputation: 41

Since other people already answered your question here's a quick tip when dealing with big numbers: you can use "_" to separate the digits of your numbers as you wish:

n = 50_000_000_000

is the same as

n = 50000000000

but the former is much easier on the eyes

Upvotes: 3

Sanjay
Sanjay

Reputation: 349

One other possibility is to increase you computers vitual memory. It helped me in my code. I had a max 3000MB virtual memory, when I increased it to 5000MB the memory error was gone.

Upvotes: 0

Tenchi2xh
Tenchi2xh

Reputation: 300

The size of the list you are generating (which is 50 billion not 5).

An int object instance takes 24 bytes (sys.getsizeof(int(899999)), the upper limit of your random numbers), so that list would take 50,000,000,000 * 24 bytes, which is about 1.09 TB.

In other words to create such a list you would need at least 1118 GB of RAM in your computer.

I don't know what your use case is, but you should consider a different approach to what you are trying to solve (maybe define a generator, or just don't store your numbers in memory and instead directly use the numbers in the for loop).

Upvotes: 10

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