Using libraries such as click and optparse we can send parameters to Python scripts when we run them from the command line. For example, passing a parameter called count with a value of 2 to a script called hello.py:
hello.py --count=2
How can I replicate this functionality in a cell of a Jupyter notebook? I like to run the same code in the notebook so that I can easily copy it to a stand alone script. Using sys.argv to pass parameters to the main function seemed one way to go and works with optparse:
from optparse import OptionParser
import sys
def main():
parser = OptionParser()
parser.add_option('-f', '--fake',
default='False',
help='Fake data')
(options,args) = parser.parse_args()
print('options:{} args: {}'.format(options, args))
if options.fake:
print('Fake detected')
def test_args():
print('hello')
if __name__ == '__main__':
sys.argv = ['--fake', 'True' '--help']
main()
output:
options:{'fake': 'False'} args: ['True--help']
Fake detected
Click seems to be flavor of the month, but I kept on getting a screen full of errors when I tried to run click through a Jupyter notebook cell. If we consider the Click example code:
import click
@click.command()
@click.option('--count', default=1, help='Number of greetings.')
@click.option('--name', prompt='Your name',
help='The person to greet.')
def hello(count, name):
"""Simple program that greets NAME for a total of COUNT times."""
for x in range(count):
click.echo('Hello %s!' % name)
if __name__ == '__main__':
hello()
If this file is called hello.py, then running from a command line:
hello.py 'Max' --count=3
Gives this output:
Hello Max! Hello Max! Hello Max!
But using the same sys.argv trick that works with optparse produces a screen full of errors when the same code is run from a Jupyter notebook cell. The solution is to put the %%python magic at the start of the cell:
%%python
import sys
import click
@click.command()
@click.option('--count', default=1, help='Number of greetings.')
@click.option('--name', prompt='Your name',
help='The person to greet.')
def hello(count, name):
"""Simple program that greets NAME for a total of COUNT times."""
with open('echo.txt', 'w') as fobj:
for x in range(count):
click.echo('Hello %s!' % name)
if __name__ == '__main__':
# first element is the script name, use empty string instead
sys.argv = ['', '--name', 'Max', '--count', '3']
hello()
A small tip, but one which cost me an hour or two of pondering. Finally I asked the hive mind of Stackoverflow. Please see this stackoverflow solution.