A question about input in Python

Question

This is somewhat of a simple question and I hate to ask it here, but I can't seem the find the answer anywhere else: is it possible to get multiple values from the user in one line of Python?

For instance, in C I can do something like this: scanf("%d %d", &var1, &var2). However, I can't figure out what the Python equivalent of that is. I figured it would just be something like var1, var2 = input("Enter two numbers here: "), but that doesn't work and I'm not complaining because it wouldn't make a whole lot of sense if it did.

Does anyone out there know a good way to do this elegantly and concisely?

Answer 1

You can't really do it the C way (I think) but a pythonic way of doing this would be (if your 'inputs' have spaces in between them):

raw_answer = raw_input()
answers = raw_answer.split(' ') # list of 'answers'

So you could rewrite your try to:

var1, var2 = raw_input("enter two numbers:").split(' ')

Note that this it somewhat less flexible than using the 'first' solution (for example if you add a space at the end this will already break).

Also be aware that var1 and var2 will still be strings with this method when not cast to int.

Answer 2

The Python way to map

printf("Enter two numbers here: ");
scanf("%d %d", &var1, &var2)

would be

var1, var2 = raw_input("Enter two numbers here: ").split()

Note that we don't have to explicitly specify split(' ') because split() uses any whitespace characters as delimiter as default. That means if we simply called split() then the user could have separated the numbers using tabs, if he really wanted, and also spaces.,

Python has dynamic typing so there is no need to specify %d. However, if you ran the above then var1 and var2 would be both Strings. You can convert them to int using another line

var1, var2 = [int(var1), int(var2)]

Or you could use list comprehension

var1, var2 = [int(x) for x in [var1, var2]]

To sum it up, you could have done the whole thing with this one-liner:

var1, var2 = [int(x) for x in raw_input("Enter two numbers here: ").split()]

Answer 3

In Python 2.*, input lets the user enter any expression, e.g. a tuple:

>>> a, b = input('Two numbers please (with a comma in between): ')
Two numbers please (with a comma in between): 23, 45
>>> print a, b
23 45

In Python 3.*, input is like 2.*'s raw_input, returning you a string that's just what the user typed (rather than evaling it as 2.* used to do on input), so you'll have to .split, and/or eval, &c but you'll also be MUCH more in control of the whole thing.

Answer 4

All input will be through a string. It's up to you to process that string after you've received it. Unless that is, you use the eval(input()) method, but that isn't recommended for most situations anyway.

input_string = raw_input("Enter 2 numbers here: ")
a, b = split_string_into_numbers(input_string)
do_stuff(a, b)