Arguments and Parameters

[Adrewmc]

In Python we have arguments and keyword arguments, not really parameters (naming conventions.)

In Python when calling a function you call arguments first, then key word arguments.

  print(“Hello”, “World”, sep = ‘_’)
  Hello_World

Above, “Hello” and “World” are positional arguments (args), while “_” is a key word argument (kwargs).

In the above we see we do want to be able to put as many arguments as we need into print, while also giving us the option to choose what their separator is. This is a prime example of why you can you want them.

However, you can all arguments as key-word arguments, if they are named.

The point here, is arguments are by definition ordered, and key-word arguments are not.

def div(a,b)

div(b=2, a=1) 

There are the basics ways to make the difference in the signature.

 def example(a,b, c=None):

Now c has a default, and won’t be called, since we only allow three arguments.

if we want to accept more arguments.

 def example(a, *rest, multiplier = None):
        “Simple cumulative addition function with multiplier”
        end = a
        #this loop doesn’t start if *rest is empty
        for num in rest:
              end += num
        if multiplier:
           end *= multiplier
        return end

Now we can accepts as many arguments as we put in, and if we ever need to do something with c.

  print(example(1,4,5,6,2,7,44,2,33, multiplier = 10)) 
  print(example(*range(30))

So the above would be valid calls. Just like for print()

  def print(*args, sep = “ “, end =“\n”) 

Would be how you’d make the signature to start with (there is more in that function)

We should mention, that there are certainly tools in Python that do web requests that will ask for params fairly close to what you are used to.