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pythonmemoryarrays
Hunter Larco
Hunter Larco

Reputation: 780

Python Large bytearray Memory

Suppose i create a large bytearray. Lets say 1000000 bytes or 1mb total. Does the interpreter reserve 1mb in memory or use memory as the byte array fills. Meaning does a mostly empty bytearray of 1000000 bytes used 1mb in memory?

Upvotes: 1

Views: 4192

Answers (2)

unutbu
unutbu

Reputation: 880877

sys.getsizeof returns the size of an object in bytes:

In [242]: sys.getsizeof(bytearray(10**6))
Out[242]: 1000025

So indeed bytearray(10**6) uses about 1MB of space.

Note that while sys.getsizeof gives an accurate answer for bytearrays, if applied to a container such as a list, it only gives the size of the container, not including the container's contents.

If you need to compute the size of an object including its contents, there is a recipe (referenced in the docs) for that.

Upvotes: 2

Torkel Bjørnson-Langen
Torkel Bjørnson-Langen

Reputation: 1014

I think it is allocated/reserved on construction. The line bellow will increase the memory usage of the interpreter by ~100MB on my system.

b = bytearray(1024*1024*100)

If the documentation does not mention it, I guess its up to the implementation.

Upvotes: 3

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