Passing list and dictionary type parameter with Python

Question

When I run this code

def func(x, y, *w, **z):
  print x
  print y
  if w:
      print w

  if z:
      print z
  else:
      print "None"

func(10,20, 1,2,3,{'k':'a'})

I get the result as follows.

10
20
(1, 2, 3, {'k': 'a'})
None

But, I expected as follows, I mean the list parameters (1,2,3) matching *w, and dictionary matching **z.

10
20
(1,2,3)
{'k':'a'}

Q : What went wrong? How can I pass the list and dictionary as parameters?

Added

func(10,20, 10,20,30, k='a')

seems to be working

Those, like me, unfamiliar with the * and ** syntax, can refer to e.g. this: stackoverflow.com/questions/1141504/… — Jonik
– Jonik, Commented Apr 26, 2010 at 18:24

Daniel Stutzbach · Accepted Answer · 2010-04-26 18:13:24Z

7

Put two asterisks before the dictionary:

func(10,20, 1,2,3,**{'k':'a'})

answered Apr 26, 2010 at 18:13

Daniel Stutzbach

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1 Comment

Michael Herold Over a year ago

This gives what the OP wants.

dash-tom-bang · Accepted Answer · 2010-04-26 18:18:59Z

2

I'm not sure what the "input" format is, but this will work:

func(10,20, 1,2,3, k='a')

With this, you don't even need to put the k=a out there at the end, it can be anywhere after the first two arguments. Then the 1,2,3 and other "unnamed" arguments get stuffed into a tuple (I think?) for the single-star arg.

answered Apr 26, 2010 at 18:18

dash-tom-bang

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Comments

Michael Herold · Accepted Answer · 2010-04-26 18:17:45Z

1

If you want to be extra explicit, you can do

func(10,20,*[1,2,3],**{'k':'a'})

to specify (to the reader) which argument you want to go with each special-form parameter.

answered Apr 26, 2010 at 18:17

Michael Herold

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