CODEWITHSUNDEEP
pythonpython-2.7
Jade
Jade

Reputation: 13

Python, Basic Function Confusion

I'm very new to python, so I'm very very confused about what is wrong with the function. Basically, I want to make a function that check if x is integer, if it is, then it should evaluate it as "positive" or "negative." If not, then I want it to return "not int" as a result.

Here are the function that I tried to fix back and forth for some time now.

def negativeIntAlert(x):

  if x != int(x):
     return "not int"
  else:
     if x >= 0:
      return "positive"
     else:
      return "negative"

I do not understand why it doesn't work like it should, because it gives me "not int" almost every time. I also have problems with Boolean type such as: negativeIntAlert(True) and it gives me "positive" instead of "not int", anything I can do to make Boolean = "not int" in this particular function?

Upvotes: 1

Views: 140

Answers (3)

simpletron
simpletron

Reputation: 739

You may try something like

def negativeIntAlert(x):
   if not isinstance(x, int):
       return "not int"
   else:
       if x >= 0:
           return "positive"
       else:
           return "negative"

Update You want to solve the bool problem, so use type instead

   if type(x) != int:
       return "not int"

Upvotes: 3

sudeep Krishnan
sudeep Krishnan

Reputation: 678

You can try this instead using if condition

def negativeIntAlert(x):
    try:    
        x = int(x)

        if x >= 0:
            return "positive"
        else:
            return "negative"
    except:
        print ("it is no an int")

Upvotes: 0

wolendranh
wolendranh

Reputation: 4292

For historical reason Boolean are inherited from int, so isinstance(True, int) will give you True, from PEP-0285:

This PEP proposes the introduction of a new built-in type, bool, with two constants, False and True. The bool type would be a straightforward subtype (in C) of the int type, and the values False and True would behave like 0 and 1 in most respects (for example, False==0 and True==1 would be true) except repr() and str(). All built-in operations that conceptually return a Boolean result will be changed to return False or True instead of 0 or 1; for example, comparisons, the "not" operator, and predicates like isinstance().

So this would be better:

def negativeIntAlert(x):
    if isinstance(x, int) and not isinstance(x, bool):
        if x >= 0:
            return "positive"
        else:
            return "negative"
    else:       
        return "not int"

Upvotes: 2

Related Questions