On Fri, Aug 6, 2010 at 10:20 AM, Rahul R <rahul8...@gmail.com> wrote: > i was writing some basic code . for understanding lambda functions , but > couldnt understand the difference between a lambda function and an ordinary > function. > > for example > >>>>def f (x): return x**2 > ... >>>> print f(8) >>>> 64 >>>> g = lambda x: x**2 >>>> >>>> print g(8) >>>> 64 > > wats a need for using lambda functions ..?
You mean "what's the need for using lambda functions?" Lambda functions are anonymous functions, ie., functions without a name. Along with map, reduce, filter, lambda functions provide functional programming[1] constructs to python. You can write code like this: from operator import add print reduce(add, filter(lambda x: x%2==0, xrange(10))) to print the sum of even numbers less than 10 instead of: tot = 0 for i in xrange(10): ....if i%2 == 0: ........tot += i print tot ... Anyway, One does not "need" to use lambda function. Almost in all the places where you use lambda functions, you can replace it with a named function with added benefit of clarity. Python lambdas are limited to a single statement, which makes them particularly hobbled. Guido is not very fond of FP constructs, in fact he wanted to remove them from python 3. After much discussion, lambda survived in Py3. [1] http://en.wikipedia.org/wiki/Functional_programming _______________________________________________ BangPypers mailing list BangPypers@python.org http://mail.python.org/mailman/listinfo/bangpypers
