Unzipping multiple .gz files into single text file using Python

Question

I am trying to unzip multiple.gz extentions files into single.txt file. All these files have json data.

I tried the following code:

from glob import glob
import gzip

for fname in glob('.../2020-04/*gz'):
    with gzip.open(fname, 'rb') as f_in:
     with open('.../datafiles/202004_twitter/decompressed.txt', 'wb') as f_out:
        shutil.copyfileobj(f_in, f_out)

But the decompressed.txt file only has the last.gz file's data.

Answer 1

Just shuffle f_out to the outside, so you open it before iterating over the input files and keep that one handle open.

from glob import glob
import gzip

with open('.../datafiles/202004_twitter/decompressed.txt', 'wb') as f_out:
    for fname in glob('.../2020-04/*gz'):
        with gzip.open(fname, 'rb') as f_in:
            shutil.copyfileobj(f_in, f_out)

Answer 2

Use "wba" mode instead. a opens in append mode. w alone will erase the file upon opening.