Multiple variables from single line in Python?

Question

I'm trying to figure out how have something like "Enter an expression: " take in 3 variables: the first int, the character of the operation, and the second int. This is very easy in C++ with just cin >> num1 >> operation >> num2.

So far, per others' questions, I've tried taking in a list and splitting it. This works, except for integers with more than 1 digit. I'm doing something like this:

list1=raw_input()
list1.split()
print list1
num1=list1[0]
plus=list1[1]
num2=list1[2]
print num1, plus, num2

For example, entering 10+3 would output 1 0 + I feel like there's a simple fix here, but I don't know it. Any help is appreciated.

Ignacio Vazquez-Abrams · Accepted Answer · 2012-04-15 04:22:23Z

1

Strings are immutable, so you need to capture the result of list1.split() somewhere. But it won't help you, since that won't do what you want. Use a parser, possibly using Python's language services.

answered Apr 15, 2012 at 4:22

Ignacio Vazquez-Abrams

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Comments

Óscar López · Accepted Answer · 2012-04-15 04:24:02Z

1

Try this instead:

list1 = raw_input()
for x in list1.split():
    print x,

answered Apr 15, 2012 at 4:24

Óscar López

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2 Comments

Óscar López Over a year ago

@IgnacioVazquez-Abrams there, fixed it.

Ignacio Vazquez-Abrams Over a year ago

The IndexError is gone, but this still won't do what the asker wants.

bereal · Accepted Answer · 2012-04-15 04:41:12Z

0

I'd suggest using regex for this case, for example:

 re_exp = re.compile(r'\s*(\d+)\s*([^\d\s])+\s*(\d+)')
 expr = raw_input()
 match = re_exp.match(expr)
 if match:
     num1, oper, num2 = match.groups()
     print num1, oper, num2

With split, you can parse 10 + 1 but it will be harder to do with 10+1 (without spaces), or to handle both cases.

answered Apr 15, 2012 at 4:41

bereal

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1 Comment

Maddy Byahoo Over a year ago

yeah, i just realized that. thanks! It's just for me (the program) so I don't need to deal with lack of spaces.

SACHIN TIWARI · Accepted Answer · 2016-06-05 20:34:22Z

0

#You should write like this
list1 = raw_input()
a=list1.split()
num1=a[0]
plus=a[1]
num2=a[2]
print num1, plus, num2

answered Jun 5, 2016 at 20:34

SACHIN TIWARI

1

1 Comment

DrewT Over a year ago

Hey, welcome to SO. Would be great if you could explain your code and give examples why op "should write like this".

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