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I am trying to calculate the square root of a number to where it looks like this:

Enter number for square root: 2
---------------------------------
.41

However, with the current code I have: 

def calc(self, event=None):
    try:
        self.result_var.set("The square root of %s is %0.2f" % \
            (self.number.get(), sqrt(float(self.number.get()))) )

I get 1.41.

How do I remove the "1" so it only displays ".41?"

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  • 1
    cast to int and subtract? num - int(num) , just like all the oldsckool cool c kids. Commented May 23, 2013 at 4:32
  • 2
    The square root of 2 isn't 0.41. Your current code is right. If you want to remove the integer part, you can do n % 1. Commented May 23, 2013 at 4:37
  • @Blender, I know, however I need it to display only the decimal places. To be more correct, I'll edit my print to "The approximate decimal square root is" Commented May 23, 2013 at 4:38
  • @Blender -- Note that % 1 doesn't give the decimal part for negative numbers. That's not a concern if you're getting the number from a square root, but ... in general I suppose it could be. Commented May 23, 2013 at 4:51

1 Answer 1

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4

You can use divmod to split a number into it's integer part and decimal part:

>>> divmod(1.41,1)
(1.0, 0.4099999999999999)

so,

intpart,decimalpart = divmod(number,1)

I suppose to get this to work for negative numbers, you'd need something like:

_,decimalpart = divmod(abs(number),1)

or more succinctly:

decimalpart = abs(number) % 1
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