>>> def make_incrementor (n): return lambda x: x + n>>>>>> f = make_incrementor(2)>>> g = make_incrementor(6)>>>>>> print f(42), g(42)44 48>>>>>> print make_incrementor(22)(33)55
The above code defines a function "make_inrementor" that creates an anonymous function on the fly and returns it. The returned function increments its argument by the value that was specified when it was created.
You can now create multiple different incrementor functions and assign them to variables, then use them independent from each other. As the last statement demonstrates, you don't even have to assign the function anywhere -- you can just use it instantly and forget it when it's not needed anymore.
The following takes this a step further.
>>> foo = [2, 18, 9, 22, 17, 24, 8, 12, 27]>>>>>> print filter(lambda x: x % 3 == 0, foo)[18, 9, 24, 12, 27]>>>>>> print map(lambda x: x * 2 + 10, foo)[14, 46, 28, 54, 44, 58, 26, 34, 64]>>>>>> print reduce(lambda x, y: x + y, foo)139