Can a variable number of arguments be passed to a function

Question

In a similar way to using varargs in C or C     fn a  b  fn a  b  c  d

User · Accepted Answer

Yes  You can use  args as a non-keyword argument  You will then be able to pass any number of arguments   def manyArgs  arg     print  I was called with   len arg    arguments    arg   gt  gt  gt  manyArgs 1  I was called with 1 arguments   1    gt  gt  gt  manyArgs 1  2  3  I was called with 3 arguments   1  2  3    As you can see  Python will unpack the arguments as a single tuple with all the arguments   For keyword arguments you need to accept those as a separate actual argument  as shown in Skurmedel s answer

User · Answer

If I may  Skurmedel s code is for python 2  to adapt it to python 3  change iteritems to items and add parenthesis to print  That could prevent beginners like me to bump into  AttributeError   dict  object has no attribute  iteritems  and search elsewhere  e g  Error      dict  object has no attribute  iteritems      when trying to use NetworkX s write shp    why this is happening   def myfunc   kwargs   for k v in kwargs items       print   s    s     k  v    myfunc abc 123  efh 456    abc   123   efh   456   and   def myfunc2  args    kwargs      for a in args         print a     for k v in kwargs items           print   s    s     k  v    myfunc2 1  2  3  banan 123    1   2   3   banan   123

User · Answer

def f dic       if  a  in dic          print dic  a            pass     else  print  None        if  b  in dic          print dic  b            pass     else  print  None        if  c  in dic          print dic  c            pass     else  print  None       print     pass f     f   a  20      c  30   f   a  20      c  30      b   red                   the above code will output  None None None 20 None 30 20 red 30   This is as good as passing variable arguments by means of a dictionary

User · Answer

Adding to the other excellent posts   Sometimes you don t want to specify the number of arguments and want to use keys for them  the compiler will complain if one argument passed in a dictionary is not used in the method    def manyArgs1 args     print args a  args b  note args c is not used here  def manyArgs2 args     print args c  note args b and  c are not used here  class Args  pass  args   Args   args a   1 args b   2 args c   3  manyArgs1 args   outputs 1 2 manyArgs2 args   outputs 3   Then you can do things like  myfuns    manyArgs1  manyArgs2  for fun in myfuns    fun args

User · Answer

Adding to unwinds post   You can send multiple key-value args too   def myfunc   kwargs         kwargs is a dictionary      for k v in kwargs iteritems             print   s    s     k  v   myfunc abc 123  efh 456    abc   123   efh   456   And you can mix the two   def myfunc2  args    kwargs      for a in args         print a    for k v in kwargs iteritems           print   s    s     k  v   myfunc2 1  2  3  banan 123    1   2   3   banan   123   They must be both declared and called in that order  that is the function signature needs to be  args    kwargs  and called in that order

User · Answer

Another way to go about it  besides the nice answers already mentioned  depends upon the fact that you can pass optional named arguments by position  For example    def f x y None       print x      if y is not None          print y    Yields  In  11   f 1 2  1 2  In  12   f 1  1

[python] Can a variable number of arguments be passed to a function?

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