[Tutor] Question on how to do exponents

Steven D'Aprano steve at pearwood.info
Tue Feb 7 02:07:08 CET 2012


On Mon, Feb 06, 2012 at 04:54:57PM -0800, William Stewart wrote:
> Hello everyone, I am making a calculator and I need to know how to make it do exponents and remainders
> How can I input this info in python?
> Any help would be appreciated

You can do exponents either with the ** operator or the pow() 
function:

py> 2**4
16
py> pow(3, 5)
243


The pow() function is especially useful for advanced mathematics where 
you want to perform exponents modulo some base:

py> pow(3, 5, 2)
1

That is, it calculates the remainder when divided by 2 of 3**5 *without* 
needing to calculate 3**5 first. This is especially useful when 
the intermediate number could be huge:

py> pow(1357924680, 2468013579, 1256711)
418453L


To get the remainder, use the % operator or the divmod() function:

py> 17 % 2
1
py> divmod(17, 2)
(8, 1)


Hope this helps.

P.S. please don't hijack threads by replying to an existing message, as 
it could lead to some people not seeing your email. It is better to 
start a new thread by using "New Message", not with "Reply".


-- 
Steven



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