Help with map python 2

Alec Taylor alec.taylor6 at gmail.com
Sun Jan 4 12:47:32 CET 2015


map(lambda i: -i if i&1==1 else i, xrange(2, 10))

On Sun, Jan 4, 2015 at 10:34 PM, flebber <flebber.crue at gmail.com> wrote:
> In repsonse to this question: Write a program that prints the first 100 members of the sequence 2, -3, 4, -5, 6, -7, 8.
>
> This is my solution it works but ugly.
>
> series = range(2,100)
> # answer = [(x,(y* -1)) for x, y in series[::2]]
> # print(answer)
> answer = []
> for item in series:
>     if item % 2 != 0:
>         answer.append(item * -1)
>     else:
>         answer.append(item)
>
> print(answer)
>
> I know I should be better off doing this with map but cannot get it to work. I understand also that map returns a generator so this solution should only working in python2(correct me please if I am wrong).
>
> In [6]: map?
> Type:       builtin_function_or_method
> String Form:<built-in function map>
> Namespace:  Python builtin
> Docstring:
> map(function, sequence[, sequence, ...]) -> list
>
> Just getting something wrong
> list(map((lambda x: x * -1 if (x%2 != 0)), series))
> --
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