Go 覆盖 a.gz 文件并使用 Python 复制以“trex”开头的句子

Question

I need to go over a.gz file with python and copy the sentence that starts with "trex". I'm quite new to python and Linux, so I am not sure if "trex" has any meaning; hence, I treated it like a string.

The first step I did was to copy the contents of the file into a variable:

file1=gzip.open(filepath, 'r')
result=file1.read() #this works
file1.close()

Then I tried a few things- converting it into a string, then splitting through "\n"

result=str(result)
r=result.split("\n")
print(r[0]) # but this prints the entire file! Not just the first line as I expected

I tried doing the same thing without converting result into a string but to no avail.

Also, I tried copying it into a different file and then trying to find "trex" in a few methods:

output= open('test_command',"w") #also tried with 'wb' 
output.write(result) #it writes only the first line into output
print(output) #only first line...
output.close()

I also tried

result=output.readlines() #.readlines() yields an error because it isn't recognized (same for .readline)

It seems the problem lies in copying the content of the.gz file with this method.

I tried copying one line at a time:

output= open('test_command','w') #also tried with 'wb' and without converting 'result' to a string
for line in result:
    output.write(line)
output.close()

I also tried (without writing result to a new file)

for line in result:
        if line[0:4] == 'trex' :
            print(line)

I tried a few combinations of these methods as well, but to not make this question any longer and more nagging I believe these will suffice.

Answer 1

I think you missed to decode your binary file stream using the string.decode('ascii') method. Because gzipping and gunzipping a file works for me:

import gzip

content = b"""
Lots of content with the word trex in here
trex at start
another trex inlined
trex the second time infront
...and the last line with trex in it
"""

gzip.open('gziptest.gz', 'wb').write(content)
file_content = gzip.open('gziptest.gz', 'rb').read().decode('ascii')

print ( "compressed file content:\n%s\n" % file_content )

trex = [ line for line in file_content.split("\n") if line[0:4] == 'trex' ]
print ( "trex: %s" % trex )

The above example writes a compressed multi line string to a file called gziptest.gz in the current directory. Then it reads that string again and uncompresses it. At the end every line beginning with the word 'trex' is filtered and printed as list.
Output:

compressed file content:

Lots of content with the word trex in here
trex at start
another trex inlined
trex the second time infront
...and the last line with trex in it

trex: ['trex at start', 'trex the second time infront']