2 added 430 characters in body
source | link

Also this:

{-1, 1}.Mean@list

or this (looks nicer in the front end):

Mean[{-1, 1}.list\[Transpose]]

It is worth noting that the first form is considerably more time efficient than the second, though both are fast (warning, several GB RAM used):

list = RandomReal[99, {30000000, 2, 2}];

{-1, 1}.Mean@list              // Timing // First

Mean[{-1, 1}.list\[Transpose]] // Timing // First

0.1902

0.921

The second also uses about 2.5X as much memory as figured by MaxMemoryUsed[].

Also this:

{-1, 1}.Mean@list

or this (looks nicer in the front end):

Mean[{-1, 1}.list\[Transpose]]

Also this:

{-1, 1}.Mean@list

or this (looks nicer in the front end):

Mean[{-1, 1}.list\[Transpose]]

It is worth noting that the first form is considerably more time efficient than the second, though both are fast (warning, several GB RAM used):

list = RandomReal[99, {30000000, 2, 2}];

{-1, 1}.Mean@list              // Timing // First

Mean[{-1, 1}.list\[Transpose]] // Timing // First

0.1902

0.921

The second also uses about 2.5X as much memory as figured by MaxMemoryUsed[].

1
source | link

Also this:

{-1, 1}.Mean@list

or this (looks nicer in the front end):

Mean[{-1, 1}.list\[Transpose]]