[Tutor] Python root.

Alan Gauld alan.gauld at btinternet.com
Mon Apr 19 00:19:02 CEST 2010

"Aidas" <aidas at vineva.lt> wrote

> You had written how to ger root in python. The way is: 
> from math import sqrt
> print sqrt( 49 )".
> I noticed that if I write just "print sqrt(49)" I get nothing. 
> So why I need to write "from math import sqrt" 

Others have explained that you need to import the name sqrt from 
the math module because sqrt is not defined as a "built-in" Python 
function. But you can achieve the same thing using the pow() function, 
which is built in - pow(49,0.5) - or the exponentiation operator - 49 ** 0.5 
without using import...

You can read more about import and modules in the "Modules and 
Functions" topic of my tutorial and more detail still in the "Whats in a name?"


Alan Gauld
Author of the Learn to Program web site

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