Call a function with argument list in python

Question

I m trying to call a function inside another function in python  but can t find the right syntax  What I want to do is something like this   def wrapper func  args       func args   def func1 x       print x   def func2 x  y  z       return x y z  wrapper func1   x   wrapper func2   x  y  z     In this case first call will work  and second won t  What I want to modify is the wrapper function and not the called functions

User · Accepted Answer

To expand a little on the other answers   In the line   def wrapper func   args     The   next to args means  take the rest of the parameters given and put them in a list called args     In the line       func  args    The   next to args here means  take this list called args and  unwrap  it into the rest of the parameters   So you can do the following   def wrapper1 func   args     with star     func  args   def wrapper2 func  args     without star     func  args   def func2 x  y  z       print x y z  wrapper1 func2  1  2  3  wrapper2 func2   1  2  3     In wrapper2  the list is passed explicitly  but in both wrappers args contains the list  1 2 3

User · Answer

You need to use arguments unpacking    def wrapper func   args       func  args   def func1 x       print x   def func2 x  y  z       print x y z  wrapper func1  1  wrapper func2  1  2  3

User · Answer

The literal answer to your question  to do exactly what you asked  changing only the wrapper  not the functions or the function calls  is simply to alter the line  func args    to read   func  args    This tells Python to take the list given  in this case  args  and pass its contents to the function as positional arguments   This trick works on both  sides  of the function call  so a function defined like this   def func2  args       return sum args    would be able to accept as many positional arguments as you throw at it  and place them all into a list called args   I hope this helps to clarify things a little   Note that this is all possible with dicts keyword arguments as well  using    instead of

User · Answer

You can use  args and   kwargs syntax for variable length arguments   What do  args and   kwargs mean   And from the official python tutorial   http   docs python org dev tutorial controlflow html more-on-defining-functions

User · Answer

A small addition to previous answers  since I couldn t find a solution for a problem  which is not worth opening a new question  but led me here   Here is a small code snippet  which combines lists  zip   and  args  to provide a wrapper that can deal with an unknown amount of functions with an unknown amount of arguments   def f1 var1  var2  var3       print var1 var2 var3   def f2 var1  var2       print var1 var2   def f3        print  f3  empty    def wrapper a b  func list  arg list       print a      for f var in zip func list arg list           f  var      print b   f list    f1  f2  f3  a list     1 2 3    4 5        wrapper  begin    end   f list  a list    Keep in mind  that zip   does not provide a safety check for lists of unequal length  see zip iterators asserting for equal length in python

User · Answer

The simpliest way to wrap a function       func  args    kwargs        is to manually write a wrapper that would call func   inside itself       def wrapper  args    kwargs             do something before         try              return func  a    kwargs          finally                do something after   In Python function is an object  so you can pass it s name as an argument of another function and return it  You can also write a wrapper generator for any function anyFunc         def wrapperGenerator anyFunc   args    kwargs           def wrapper  args    kwargs               try                    do something before                 return anyFunc  args    kwargs              finally                   do something after         return wrapper   Please also note that in Python when you don t know or don t want to name all the arguments of a function  you can refer to a tuple of arguments  which is denoted by its name  preceded by an asterisk in the parentheses after the function name        args   For example you can define a function that would take any number of arguments       def testFunc  args           print args      prints the tuple of arguments   Python provides for even further manipulation on function arguments  You can allow a function to take keyword arguments  Within the function body the keyword arguments are held in a dictionary  In the parentheses after the function name this dictionary is denoted by two asterisks followed by the name of the dictionary         kwargs   A similar example that prints the keyword arguments dictionary       def testFunc   kwargs           print kwargs      prints the dictionary of keyword arguments

[python] Call a function with argument list in python

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