How to pass default & variable length arguments together in python?

Question

I found many queries on python function arguments but still left confused. Suppose I want to pass few arguments in some function.

def anyFunc(name, age, sex = 'M', *cap_letters ):
    print "name ", name
    print "age ", age
    print "sex ", sex
    for s in cap_letters:
        print "capital letter: ", s

name & age arguments are positional arguments. sex is default argument followed by variable length of non keyword arguments which are few random capital alphabets. So now if I run

anyFunc("Mona", 45, 'F', *('H', 'K', 'L'))

It gives me perfect output..

name  Mona
age  45
sex  F
capital letter:  H
capital letter:  K
capital letter:  L

But if I pass below arguments where I want to use default sex value instead of passing it. Output is not as expeceted.

anyFunc("John", 45, *('H', 'K', 'L'))

name  John
age  45
sex  H
capital letter:  K
capital letter:  L

It should have taken the default value of sex i.e. 'M'. I also tried to pass sex argument at the very last but it gave me syntax error. Is there any way to achieve what I want?

Answer 1

Don't use * magic in a functions signature if you also use/need it on the calling side. Then simply drop it on both sides and don't make it more complicated as it has to be:

def any_func(name, age, sex='M', capital_letters=()):
    print 'name ', name
    print 'age ', age
    print 'sex ', sex
    for capital_letter in capital_letters:
        print 'capital letter: ', capital_letter

Called as:

any_func('Mona', 45, 'F', ('H', 'K', 'L'))

And with default sex:

any_func('John', 45, capital_letters=('H', 'K', 'L'))

If you don't like spelling out the capital_letters arguments name at many calls and it is acceptable to reorder the arguments, then swap the last two arguments:

def any_func(name, age, capital_letters=(), sex='M'):
    print 'name ', name
    print 'age ', age
    print 'sex ', sex
    for capital_letter in capital_letters:
        print 'capital letter: ', capital_letter

Calls:

any_func('Mona', 45, ('H', 'K', 'L'), 'F')
any_func('John', 45, ('H', 'K', 'L'))