kwargs_stuff.py

### Define a function with kwargs


def kwargs_fun(**kwargs):
    # Just print the content of kwargs
    print(kwargs)


# Now call kwargs_fun in a few goofy ways and see what happens:

kwargs_fun(matt='short', shoe_size=9.5, hair=True)
kwargs_fun(g=9.8, foo=-9)


# Define this function for an example of how to pass kwargs
# through a function without ever looking at what is inside. This
# function is kind of like rk2 and make_solve.
def kwargs_caller(f, **kwargs):
    f(**kwargs)


# Call our new function
kwargs_caller(kwargs_fun, g=10, planet='earth')


# A revised version of our "func" from lecture:
def func(conditions, t, g=9.8):
    y = conditions[0]
    vy = conditions[1]

    # print the value of g just to see what its value is in here
    print("Field strength is ", g)

    return [vy, -g]


# One last definition, a revised kwargs_caller that passes on
# conditions and time


def kwargs_caller2(f, cond, t, **kwargs):
    f(cond, t, **kwargs)

# Initials conditions
cond_init = [0, 0.0]
t = 0.0

# And call it with our caller (which is like rk2 or make_solve):
kwargs_caller2(func, cond_init, t, g=5)  # Works, and g=5 in func

kwargs_caller2(func, cond_init, t)  # Works, and g=9.8, the default, in func

kwargs_caller2(func, cond_init, t, g=9.8 / 6, planet='moon')  # FAILS because func does not have argument planet