create file of particular size in python

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WARNING This solution gives the result that you might not expect. See UPD …

1 Create new file.

2 seek to size-1 byte.

3 write 1 byte.

4 profit 🙂

f = open('newfile',"wb")
f.seek(1073741824-1)
f.write(b"\0")
f.close()
import os
os.stat("newfile").st_size

1073741824

UPD:
Seek and truncate both create sparse files on my system (Linux + ReiserFS). They have size as needed but don’t consume space on storage device in fact. So this can not be proper solution for fast space allocation. I have just created 100Gib file having only 25Gib free and still have 25Gib free in result.

Minor Update:
Added b prefix to f.write("\0") for Py3 compatibility.

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