biginteger array functions

问题

Are there any available functions for work with big integers?

I've found a module intarray, but functions from this module only work with integer, not bigint.

I miss a function for removing an item from an array. Something like the implementation of a "minus" operator in mentioned module:

int[] - int (remove entries matching right argument from array)

回答1:

^{Updated 2015 with a better version.}
You can substitute your own function. This one is reasonably fast:

CREATE OR REPLACE FUNCTION arr_subtract(int8[], int8[])
  RETURNS int8[] AS
$func$
SELECT ARRAY(
    SELECT a
    FROM   unnest($1) WITH ORDINALITY x(a, ord)
    WHERE  a <> ALL ($2)
    ORDER  BY ord
    );
$func$  LANGUAGE sql IMMUTABLE;

Call:

SELECT arr_subtract('{3,5,6,7,8,9}':: int8[], '{3,4,8}'::int8[]);

Result:

{5,6,7,9}

Keeps the original order of the array.

Related:

• PostgreSQL unnest() with element number
• Exclude matched array elements

来源：https://stackoverflow.com/questions/8579701/biginteger-array-functions