CODEWITHSUNDEEP
pythonfunctionpython-3.xdefault-value
lol
lol

Reputation: 481

Input as a default value for a function

Is it possible to have input as a default value for a function?

For example,

f(x=input('>')):
    print(x)

The problem is, it makes me input a value even when I supply an x value. How would I do this correctly?

Upvotes: 2

Views: 2944

Answers (2)

Dimitris Fasarakis Hilliard
Dimitris Fasarakis Hilliard

Reputation: 160377

Python will evaluate the default arguments you define for a function, you'll get the prompt during definition either you like it or not. The value entered at the input prompt will then be assigned as the default for x.

If you want a default value that will use input if no other meaningful value is provided, use the common idiom involving None and drop input in the body of the function, instead:

def f(x=None):
    if x is None:
        x = input('> ')
    print(x)

Now, if you're thinking, I still want to somehow do this with default arguments, then you'll need to create a function that re-creates your function with every invocation:

def f():
    def _(x = input('> ')):
        print(x)
    return _()

I don't see what benefit this would bring other than appeasing your curiosity, though :-)

Upvotes: 4

gipsy
gipsy

Reputation: 3859

May be this is what you want.

def f(x=None):
  if not x:
    x = input('>')
  print(x)

Upvotes: 1

Related Questions