Dynamic default arguments in python functions

Question

I have a need for functions with default arguments that have to be set at function runtime (such as empty lists, values derived from other arguments or data taken from the d

Answer 1

You could do something like this:

def getArg():
  try:
      return arg
  except NameError:
      return 0

def foo(x, y=getArg):
    y = y()
    print(y)

foo(1) # Prints 0 (Default)

arg = 7 # Set by argparse?

foo(2)           # Prints 7 (Dynamic global)
foo(3, lambda:9) # Prints 9 (Dynamic passed)