Hello! Please take a look at the example.
>>> a = [(x, y) for x, y in map(None, range(10), range(10))] # Just a list of >>> tuples >>> a [(0, 0), (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6), (7, 7), (8, 8), (9, 9)] Now i want to get a list of functions x*y/n, for each (x, y) in a: >>> funcs = [lambda n: x * y / n for x, y in a] It looks consistent! >>> funcs [<function <lambda> at 0x010F3DF0>, <function <lambda> at 0x010F7CF0>, <function <lambda> at 0x010F7730>, <function <lambda> at 0x010FD270>, <function <lambda> at 0x010FD0B0>, <function <lambda> at 0x010FD5B0>, <function <lambda> at 0x010FD570>, <function <lambda> at 0x010FD630>, <function <lambda> at 0x01100270>, <function <lambda> at 0x011002B0>] ...and functions are likely to be different. >>> funcs[0](1) 81 But they aren't! >>> for func in funcs: ... print func(1) ... 81 81 81 81 81 81 81 81 81 81 It seems, all functions have x and y set to 9. What's wrong with it? Is it a bug? On the other hand, this problem has a solution: >>> def buldFunc(x, y): ... return lambda n: x * y / n ... >>> funcs = [buldFunc(x, y) for x, y in a] ... and it does work! But why not to save several lines of code? ;) Thanks in advance. -- http://mail.python.org/mailman/listinfo/python-list
