How to round a number to n decimal places?

Question

I want, what I enter in the entry field should be automatic rounded to n decimal points.

import Tkinter as Tk

root = Tk.Tk()

class InterfaceApp():
    def __in         


        

Answer 1

I suppose what you want is not to round the float value itself, you want to show a float value with a precision of n decimal points. Try this:

>>> n = 2
>>> '{:.{}f}'.format( 3.1415926535, n )
'3.14'
>>> n = 3
>>> '{:.{}f}'.format( 3.1415926535, n )
'3.142'

Note: in your code you try to round self.entry .i. e. you try to round an instance of type Tk.Entry. You should use self.entry.get() which supplies you with a string.

If you are not familiar with this kind of string formatting I use look here.