# [Tutor] Livewires questions

Eric Brunson brunson at brunson.com
Thu Jul 26 20:47:48 CEST 2007

```Tiger12506 wrote:
>> Based on your guidance, I figured it out.  I need to use a return
>> statement, which I had not encountered before.  Now I wrote my
>> definitions in this way:
>>
>> def collided():
>>    if player_x == robot_x+0.5 and player_y == robot_y+0.5:
>>       return True
>>

Granting that I have not looked at any of the Livewires modules, I just
wanted to say...

A general check for collision would probably involve the distance
formula from geometry

collided( (x1,y1), (x2,y2) ):
return( sqrt( (x1-x2)**2 + (y1-y2)**2 ) < 1 )

but could probably be simplified to something like:

def collided( (x1,y1), (x2,y2) ):
return( abs( x1 - x2 ) < .5 and abs( y1 - y2 ) < .5 )

>
> This could be simplified more.
> Here's an example as a hint. These two functions are the same.
>
> def f():
>   if a == b and c == d:
>     return True
>
> def g():
>   return (a==b and c == d)
>
>
>
>> Then I use that value in another definition like this:
>>
>> def check_collisions():
>>    if collided() == 1:
>>       print "You have been caught"
>>
>
> And ~
>
> if collided():
>   print "You have been caught"
>
> _______________________________________________
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>

```