# calculation on lists

loïc Lauréote laureote-loic at hotmail.fr
Wed Dec 19 16:24:11 CET 2012

```Thank for your answer,

I found something allowing to avoid loops.

import math

class Vector:
def __init__(self, x=0, y=0):
self.x=x
self.y=y
def __eq__(self, vB): return (self.x==vB.x) and (self.y==vB.y)
def __sub__(self, vB):  return Vector(self.x-vB.x,self.y-vB.y)
def __mul__(self, c):
if isinstance(c,Vector): return  Vector(self.x*c.x,self.y*c.y)
else: return Vector(c*self.x,c*self.y)

def __div__(self, c):
if isinstance(c,Vector): return  Vector(self.x/c.x,self.y/c.y)
else: return Vector(c*self.x,c*self.y)

a = Vector(4,5)
b = Vector(6,7)
print a,b
print b*b+a

thx

> Date: Wed, 19 Dec 2012 13:38:28 +0100
> Subject: Re: calculation on lists
> From: vlastimil.brom at gmail.com
> To: laureote-loic at hotmail.fr
> CC: python-list at python.org
>
> 2012/12/19 loïc Lauréote <laureote-loic at hotmail.fr>:
> hi,
> I
>  have a question,
> is there a tool to calculate on list ?
>
> something like :
>
> >a= [1,1,1,1]
> >b = [5,9,8,4]
> >c = a+b*a
> >print c
> >[6,10,9,5]
>
> Thx
>
> ======
>
> Hi,
> for such simpler cases, you may try list comprehensions and probably
> the zip(...) function
>
> >>> [a+b*a for a,b in zip([1,1,1,1], [5,9,8,4])]
> [6, 10, 9, 5]
> >>>
>
> hth,
>   vbr

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-list/attachments/20121219/34b11189/attachment.html>
```