About lambda.

[Xin Wang]

Some c++ guru said c++ is hard to learn but easy to
use. Is python easy for both aspect? I found lot's of
confused in coding.

#code
from Tkinter import *

def on_click(m):
print m
def lamb_on_click(m):
return lambda : on_click(m)
root = Tk()
btns = ['0', '1', '2', '3']
for n in btns:
b = Button(root, text=n, command=lamb_on_click(n))
#Ok!
b.pack()
root.mainloop()
#

Or,

#code
....
b = Button(root, text=n, command=lambda x=n:
click(x)) #Ok!
....
#

The code above works well too, but follow is NOT! WHY?

#code
....
b = Button(root, text=n, command=lambda :
on_click(n))
....
#

Whichever button be clicked, this only print '3'.

Keyword 'lambda' is just like a macro in c or templete
in c++ or not?




_______________________________
Do you Yahoo!?
Declare Yourself - Register online to vote today!
http://vote.yahoo.com

 

[Ville Vainio]

Xin> Some c++ guru said c++ is hard to learn but easy to use. Is

I would question such a guru. There is nothing "easy to use" about
C++. Or perhaps the Guru hadn't tried any other modern language apart
from C.