[Tutor] lambda

[Alan Gauld]

On 25/01/13 23:57, anthonym wrote:

> I don't think my classmates will understand the use of lambda here but I
> am having are hard time converting that to strictly python.

lambdas are strictly python but they can be easily reanslated into a 
named function as

lambda p: expr

becomes

def f(p):
    return expr

so in your case

 >          b[i][j] = Button(font=('Aerial', 56), width=3, bg='yellow',
 >                           command = lambda r=i,c=j: ttt(r,c))

becomes

def bCmd(r=i,c=j):
     return ttt(r,c)

b[i][j] = Button(font=('Aerial', 56), width=3, bg='yellow',
                  command = bCmd)

Your problem of course is that you need i and j to be dynamically 
defined so you need to create and call a function that returns a 
function like this

def buttonFunMaker(i,j):
     def func(x=i,y=j):
         return ttt(x,y)
     return func

b[i][j] = Button(font=('Aerial', 56), width=3, bg='yellow',
                  command = buttonFunMaker(i,j))

Personally I prefer the lambda...

HTH

-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/