Can't run file with sys.arg[1]

Question

I'm working through https://testdriven.io/developing-an-asynchronous-task-queue-in-python . I've also taken a look at sys.argv[1] meaning in script for clarification on sys.argv

From the former I have:

def save_file(filename, data):
    random_str = uuid.uuid4().hex
    outfile = f'{filename}_{random_str}.txt'
    with open(os.path.join(OUTPUT_DIRECTORY, outfile), 'w') as outfile:
        outfile.write(data)


def get_word_counts(filename):
    wordcount = collections.Counter()
    # get counts
    with open(os.path.join(DATA_DIRECTORY, filename), 'r') as f:
        for line in f:
            wordcount.update(line.split())
    for word in set(COMMON_WORDS):
        del wordcount[word]
    # save file
    save_file(filename, json.dumps(dict(wordcount.most_common(20))))
    # simulate long-running task
    time.sleep(2)
    proc = os.getpid()
    print(f'Processed {filename} with process id: {proc}')


if __name__ == '__main__':
    print(sys.argv, len(sys.argv))
    # print(sys.argv[1], len(sys.argv))
    get_word_counts(sys.argv[1])

When I run it directly with I get:

$ python tasks.py
['tasks.py'] 1
Traceback (most recent call last):
 File "tasks.py", line 46, in <module>
get_word_counts(sys.argv[1])
IndexError: list index out of range

Given that you can see there is only one element in the list, why did the author write the the code in this way?

Perhaps the intention was to always call the script with some argument: `python tasks.py afile.log`. In this way you would get a second element in the `sys.argv list`. — Moberg, Aug 03 '18 at 14:25
https://stackoverflow.com/questions/4117530/sys-argv1-meaning-in-script — Sailesh Kotha, Aug 03 '18 at 14:26

score 1 · Answer 1 · answered Aug 03 '18 at 14:31

1

get_word_counts(sys.argv[1])

Should be

get_word_counts(sys.argv[0])

Indexes start at zero in most languages (including python)

answered Aug 03 '18 at 14:31

Shardj

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actually I tried it sailesh's , answer is correct You can run the program like this: $ python tasks.py st1.txt – user1592380 Aug 03 '18 at 14:58

Can't run file with sys.arg[1]

1 Answers1