How does function `flags.DEFINE_boolean` works?

Question

I'm confused about the function flags.DEFINE_boolean when I'm using python's absl module. Below is my code, when I set the parameter default to True, I can no longer dynamically modify is_student to False via the command line.

from absl import app, flags

mmap = flags.FLAGS
flags.DEFINE_boolean(
    name='is_student',
    default=True,
    help='Are you a student?',
)


def func(_):   # 'python test.py --is_student False' doesn't work
    print(mmap.is_student)  # mmap.is_student is always True


if __name__ == '__main__':
    app.run(func)

At the same time, I found that when setting the parameter default to False, as long as the is_student is mentioned on the command line, the is_student is triggered as True. Can I just set the default value of flags.DEFINE_boolean to False?

Answer 1

--is_student False doesn't mean you're setting is_student to False. The --is_student means you're setting is_student to True, and the False is interpreted as an entirely unrelated argument.

To turn off the is_student flag, use --nois_student.