Proposals

Functions

Remove array element by offset

A function enabling one to remove an element by offset from an array.

Offsets in PostgreSQL start at 1 rather than 0 like most other implementations. This concept should also be adopted by anyarray, as itself is an implementation specific to PostgreSQL.

Proposal #1

Perform function overloading, where an optional third parameter is present signaling that the second argument is an offset rather than a value.

Function Name

anyarray_remove

Arguments:

1. anyarray: The array from which to remove the element from.
2. integer or `integer[]: The offset(s) at which the element(s) to be removed reside(s). Any offset(s) passed which does not exist is simply ignored.
3. boolean: Pass TRUE to inform anyarray_remove that the second argument is an offset, rather than a value.

Returns:

anyarray

Calling:

SELECT ANYARRAY_REMOVE(ARRAY[9,8,7], 2, TRUE);
-- Returns: {9,7}

SELECT ANYARRAY_REMOVE(ARRAY[9,8,7], 4, TRUE);
-- Returns: {9,8,7}

SELECT ANYARRAY_REMOVE(ARRAY[9,8,7], ARRAY[1,2,4], TRUE);
-- Returns: {7}

Proposal #2

Dedicate a function specifically to removing an element by offset.

Function Name

anyarray_offset_remove

Arguments:

1. anyarray: The array from which to remove the element from.
2. integer or `integer[]: The offset(s) at which the element(s) to be removed reside(s). Any offset(s) passed which does not exist is simply ignored.

Returns:

anyarray

Calling:

SELECT ANYARRAY_OFFSET_REMOVE(ARRAY[9,8,7], 2);
-- Returns: {9,7}

SELECT ANYARRAY_OFFSET_REMOVE(ARRAY[9,8,7], 4);
-- Returns: {9,8,7}

SELECT ANYARRAY_OFFSET_REMOVE(ARRAY[9,8,7], ARRAY[1,2,4]);
-- Returns: {7}

Map function to each element in array

A function which maps the specific function and arguments to every element within an array.

This function would support an undetermined number of arguments in arbitrary order to facilitate the mapping of any function possible.

Proposal #1

Stick to the current anyarray standard, where the first argument is always the array with which the action is being performed on.

Function Name

anyarray_map

Arguments:

Argument #1: anyarray: The array of elements which will have the function called on. Argument #2: text: The function to be called. $1 represents the element from the array. $2, $3, etc. represent additional arguments to be passed. Argument #3, #4, #...: Additional arguments to be passed to the function being mapped to.

Returns:

anyarray

Calling:

SELECT ANYARRAY_MAP(ARRAY[' a ',' b','c'], 'TRIM($1)');
-- Returns: {a,b,c}
-- Equivalent to:
--    TRIM(' a ')
--    TRIM(' b')
--    TRIM('c')

SELECT ANYARRAY_MAP(ARRAY['hi','howdy'], 'REPLACE($1, $2, $3)', 'hi', 'hello');
-- Equivalent to:
--    REPLACE('hi', 'hi', 'hello')
--    REPLACE('howdy', 'hi', 'hello')
-- Returns: {hello,howdy}

Proposal #2

It may be easier to understand what a call to array_map is doing (and perhaps easier to define a call as well,) if the function call is passed first, followed by the subject array. All additional arguments will be passed subsequently.

Function Name

anyarray_map

Arguments:

Argument #1: text: The function to be called. $1 represents the element from the array. $2, $3, etc. represent additional arguments to be passed. Argument #2: anyarray: The array of elements which will have the function called on. Argument #3, #4, #...: Additional arguments to be passed to the function being mapped to.

Returns:

anyarray

Calling:

SELECT ANYARRAY_MAP('TRIM($1)', ARRAY[' a ',' b','c']);
-- Returns: {a,b,c}
-- Equivalent to:
--    TRIM(' a ')
--    TRIM(' b')
--    TRIM('c')

SELECT ANYARRAY_MAP('REPLACE($1, $2, $3)', ARRAY['hi','howdy'], 'hi', 'hello');
-- Equivalent to:
--    REPLACE('hi', 'hi', 'hello')
--    REPLACE('howdy', 'hi', 'hello')
-- Returns: {hello,howdy}