Argparse tutorial example doesn't work in windows command line

Question

So I'm trying to teach myself how to use the python library argparse via the tutorial here. The example is given by the following piece of code which is saved as tut.py.

import argparse

parser = argparse.ArgumentParser(description='Process some integers.')
parser.add_argument('integers', metavar='N', type=int, nargs='+',
                help='an integer for the accumulator')
parser.add_argument('--sum', dest='accumulate', action='store_const',
                const=sum, default=max,
                help='sum the integers (default: find the max)')

args = parser.parse_args()
print(args.accumulate(args.integers))

In the tutorial they put a $ before every command in the command line which is due to them using Linux I think. First if I add an $ in my windows command line before any command I get the error

The "$" command was either misspelled or could not be found.

If I then run

 python tut.py 1 2 3 4

I don't get an error but neither is any output displayed in the command line. What would be expected is the sum of those integers though.

How can I make the output show up in the command prompt ?

The `$` just denotes a new line in the linux terminal, you can ignore it — C.Nivs, Dec 08 '20 at 14:35
What happens if you set `print(args.accumulate(args.integers), flush=True)`? — C.Nivs, Dec 08 '20 at 14:49
If you want to print sum of the integers, try sum() function instead of accumulate() — Hirusha Fernando, Dec 08 '20 at 14:49
@HirushaFernando OP wants to leverage the default set by the `--sum` flag, which is `max`, and if the `sum` flag is passed, it will switch to `sum` as seen by the `const` and `default` kwargs, so `args.accumulate` is correct — C.Nivs, Dec 08 '20 at 14:50
@C.Nivs setting flush = True doesn't generate any output neither — Christian Singer, Dec 08 '20 at 14:54
Can you try running `python -u -c "print('hello')"` and see if it prints anything? The `-u` is for unbuffered output — C.Nivs, Dec 08 '20 at 15:10

Christian Singer · Answer 1 · 2020-12-08T15:47:27.957

1

At the beginning I didn't think that it was important to specify that I use the anaconda distribution for python, however it turns out that using the anaconda command prompt instead of the windos 10 one solves the problem.

Output

(base) C:\Users\Admin\Desktop\HiWi\Codect>python tut.py 1 2 3 4
4

(base) C:\Users\Admin\Desktop\HiWi\Codect>python tut.py 1 2 3 4 --sum
10

(base) C:\Users\Admin\Desktop\HiWi\Codect>

edited Dec 08 '20 at 15:47

answered Dec 08 '20 at 15:42

Christian Singer

295
3
5
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score 0 · Answer 2 · answered Dec 08 '20 at 14:40

0

Use this code to get some of n passed arguments : tut.py

import argparse

parser = argparse.ArgumentParser(description='Process some integers.')
parser.add_argument('integers', metavar='N', type=int, nargs='+',
                help='an integer for the accumulator')
parser.add_argument('--sum', dest='accumulate', action='store_const',
                const=sum, default=max,
                help='sum the integers (default: find the max)')

args = parser.parse_args()
print(sum(args.integers))

OUTPUT

python tut.py 1 2 3 4   
10

Note: when I run your code it runs perfectly

answered Dec 08 '20 at 14:40

Yash Makan

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1
5
17

Hmm, interesting. It still doesn't show any output in my case – Christian Singer Dec 08 '20 at 14:47
Actually, it does. I ran the same script in my windows 10 machine and this worked. Check your cmd command – Yash Makan Dec 08 '20 at 14:50
try `echo hi` in cmd. does it print something? – Yash Makan Dec 08 '20 at 14:56
Yes it prints "hi" – Christian Singer Dec 08 '20 at 14:56
Now make a python script which simply prints hi by `print('hi')` and run by cmd. Does it print anything? – Yash Makan Dec 08 '20 at 14:57
in this case I don't get any output – Christian Singer Dec 08 '20 at 14:58
Try : if __name__ == "__main__": main() and put all code in main() function – Yash Makan Dec 08 '20 at 15:06
This doesn't work neither. Apparently the problem is not related with argparse though since even print("hi") doesn't yield any output – Christian Singer Dec 08 '20 at 15:10
Yes, ask a new question about the same in `Ask Question` – Yash Makan Dec 08 '20 at 15:12
@YashMakan OP does not have to ask a new question, your answer just doesn't answer this one – C.Nivs Dec 08 '20 at 16:05

Argparse tutorial example doesn't work in windows command line

2 Answers2

Output

Linked