functools_partial.py

#!/usr/bin/env python


import functools


def myfunc(a, b=2):
    """Docstring for myfunc()."""
    print ' called myfunc with:', (a, b)
    return


def show_details(name, f, is_partial=False):
    """Show details of a callable object."""
    print '%s:' % name
    print ' object:', f
    if not is_partial:
        print ' __name__:', f.__name__
    if is_partial:
        print ' func:', f.func
        print ' args:', f.args
        print ' keywords:', f.keywords
    return

show_details('myfunc', myfunc)
myfunc('a', 3)
print

# Set a different default value for 'b', but require
# the caller to provide 'a'.
p1 = functools.partial(myfunc, b=4)
show_details('partial with named default', p1, True)
p1('passing a')
p1('override b', b=5)
print

# Set default values for both 'a' and 'b'.
p2 = functools.partial(myfunc, 'default a', b=99)
show_details('partial with defaults', p2, True)
p2()
p2(b='override b')
print

print 'Insufficient arguments:'
p1()