Default argument and variable-length argument in python

Question

In function I've defined two arguments 1:default variable say age=12 and 2:variable-length argument say *friends

    def variable(age=12,*friends):
         print 'Age:', age
         print 'Name:', friends
         return
    variable(15,'amit','rishabh') # RESULT is "Age: 15 & Name: 'amit', 'rishabh'
    variable('rahul','sourabh') # Now here result is Age: rahul & Name: 'sourabh'

so my question is why function does'nt take both this arguments in *friends variable why it determine the first argument as age.

I need result should be in this format as:

variable(15,'name','surname') as Age:15 and Name: 'name','surname'

and if I don't assign age as

variable('new','name') Result needed to be as. Age:12 & Name:'new','name'

"why it determine the first argument as age." because that's how you defined your function. — Julien
– Julien, Commented Sep 10, 2018 at 7:03
how is your program supposed to know if the first argument is an age or a name? Maybe check for type if that's the behavior you are after... — Julien
– Julien, Commented Sep 10, 2018 at 7:04
The first argument will always be considered to be the age since you constructed your function this way. — Shintlor
– Shintlor, Commented Sep 10, 2018 at 7:05

Alexandru Martalogu · Accepted Answer · 2018-09-10 07:19:50Z

1

You could try to give in a list instead of various arguments, also keyword arguments should always go after aguments:

def variable(friends, age=12):
    print 'Age:', age
    print 'Name:', ",".join(friends)
    return
variable(['amit','rishabh'], 15) # RESULT is "Age: 15 & Name: 'amit', 'rishabh'
variable(['rahul','sourabh']) # Now here result is Age: rahul & Name: 'sourabh'

answered Sep 10, 2018 at 7:19

Alexandru Martalogu

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Comments

Shintlor · Accepted Answer · 2018-09-10 07:17:57Z

0

Try switching the arguments:

def variable(*friends,age=12):
    print ('Age:', age)
    print ('Name:', friends)
    return

This should work.

answered Sep 10, 2018 at 7:17

Shintlor

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5 Comments

Alexandru Martalogu Over a year ago

This won't work, as if you given *args,**kwargs must follow, explicit arguments must come before, (name, age=12, *args, **kwargs) this is the correct syntax

Shintlor Over a year ago

You are correct that this may not follow the correct syntax. Nevertheless it does work. The OP should accept your answer though!

Alexandru Martalogu Over a year ago

Are you sure? I'm trying it on Python 2.7 and my IDE is telling me Encountered "age" at line 268, column 23. Was expecting one of: "*" ... "**" ...

Alexandru Martalogu Over a year ago

Also running the code is giving me a Syntax Exception, might be working on Python 3?

Shintlor Over a year ago

Yes, I am running python 3.6.6 and tested it in a jupyter notebook.

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