Running a Python script in Jupyter Notebook, with arguments passing

You need to use sys.argv instead of sys.stdin.read():

two_digits.py

import sys
args = sys.argv  # a list of the arguments provided (str)
print("running two_digits.py", args)
a, b = int(args[1]), int(args[2])
print(a, b, a + b)

command line / jupyter magic line:

%run two_digits 3 5

or, with a slightly different output:
Note: this uses a ! prefix to indicate command line to jupyter

!ipython two_digits.py 2 3

output: (using magic line %run)

running two_digits.py ['two_digits.py', '2', '3']
2 3 5

%%file calc.py

from sys import argv

script, a, b, sign = argv

if sign == '+': 
    print(int(a) + int(b))
elif sign == '-':
    print(int(a) - int(b))
else:
    print('I can only add and subtract')

We have several options:

%%!
python calc.py 7 3 +

or

%run calc.py 7 3 +

or

!python calc.py 7 3 +

or with the path in output

!ipython calc.py 7 3 +

To access the output use the first way with %%!. Output is a list (IPython.utils.text.SList)

[In 1]
%%!
python calc.py 7 3 +

[Out 1]
['10']

Now you can use underscore '_'

[In 2]
int(_[0])/2  # 10 / 2

[Out 2]
5.0