How does a lambda function refer to its parameters in python?

Question

I am new in Python. My task was quite simple -- I need a list of functions that I can use to do things in batch. So I toyed it with some examples like

fs = [         


        

Answer 1

i is local and there are indeed closures in python.

I believe your confusion is that you assigh fs to a list of identical function.

>>> fs = [lambda x: x + i for i in xrange(10)]
>>> fs
[ at 0x02C6E930>,  at 0x02C6E970>,  at 0x02C6E9B0>,  at 0x02C6E9F0>,  at 0x02C6EA30>,  at 0x02C6EA70>,  at 0x02C6EAB0>,  at 0x02C6EAF0>,  at 0x02C6EB30>,  at 0x02C6EB70>]
>>> fs[0](0)
9
>>> fs[0](100)
109
>>> fs[5](0)
9
>>> fs[5](100)
109

I think a single function returning a list would be more appropriate.

>>> fs3 = lambda x: [x + i for i in xrange(10)]
>>> fs3
 at 0x02C6EC70>
>>> fs3(0)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]