Using ReplaceAll
ReplaceAll
{{0, {0.}[0]}, {1, {309.56}[1]}, {2, {123.06}[2]}, {3, {-302.53}[3]}, {4, {-136.92}[4]}} /. {a_, {b_}[_]} :> {a, b} (* {{0, 0.}, {1, 309.56}, {2, 123.06}, {3, -302.53}, {4, -136.92}} *)
Hey Marco, that's like magic. Thanks.
I suppose that there is a problem with the code that generates that list, but here is how you can clean it up:
{#[[1]], #[[2, 0, 1]]} & /@ {{0, {0.}[0]}, {1, {309.56}[1]}, {2, {123.06}[2]}, {3, {-302.53}[3]}, {4, {-136.92}[4]}}
Cheers,
Marco