Suppose I have a function with 10 args:
def foo(arg1,arg2,arg3,arg4.....):
Sometimes, I need to call it with only arg1 and another time arg1, arg4, or arg4 , arg7.
My program doesn't specify the type of the function call. Does python have a way to help me?
One way to do it is to make the parameters optional:
def foo(arg1=None,arg2=None,arg3=None...)
which can be called like this:
foo(arg1=1,arg3=2)
or like this:
a = {'arg1':1, 'arg3':2}
foo(**a)
If this list of parameters is spinning out of control you could simply use **kwargs to let your function take an optional number of (named) keyword arguments:
def foo(**kwargs):
print kwargs
params = {'arg1':1, 'arg2':2}
foo(**params) # Version 1
foo(arg1=3,arg2=4) # Version 2
Output:
{'arg1': 1, 'arg2': 2}
{'arg1': 3, 'arg2': 4}
Note: You can use one asterisk (
*) for an arbitrary number of arguments that will be wrapped up in a tuple.
Give your args a default value like None:
def foo(arg1=None, arg2=None, ..., arg10=None):
Now, when calling the function pass a dictionary of keyword arguments:
kwargs = {
'arg1': 'test',
'arg7': 'test2',
}
foo(**kwargs)
It's equivalent to:
foo('test', None, None, None, ..., 'test2', None, None, None)
Or, to be more specific:
foo(arg1='test', arg7='test2')
You could use keyword arguments
def foo(arg1 = val, arg2 = val2, arg3 = val3,...):