all_match

Description

Returns whether all elements of an array match the given predicate.

Returns true (1) if all the elements match the predicate (a special case is when the array is empty).
Returns false (0) if one or more elements do not match.
Returns NULL if the predicate returns NULL for one or more elements and true for all other elements.

Syntax

all_match(lambda_function, arr1, arr2...)

Returns whether all elements of arr1 match the given predicate in the lambda function.

Parameters

arr1: the array to match.
arrN: optional arrays used in the lambda function.
lambda_function: the lambda function used to match values.

Return value

Returns a BOOLEAN value.

Usage notes

The lambda function follows the usage notes in array_map(). It returns array<bool>.
If the input array is null or the lambda function results in null, null is returned.
If arr1 is empty, true is returned.
To apply this function to MAP, rewrite all_match((k,v)->k>v,map) to all_match(map_values(transform_values((k,v)->k>v, map))). For example, select all_match(map_values(transform_values((k,v)->k>v, map{2:1}))); returns 1.

Examples

Check whether all elements in x are less than the elements in y.

select all_match((x,y) -> x < y, [1,2,-8], [4,5,6]);
+---------------------------------------------------+
| all_match((x, y) -> x < y, [1, 2, -8], [4, 5, 6]) |
+---------------------------------------------------+
|                                                 1 |
+---------------------------------------------------+

select all_match((x,y) -> x < y, [1,2,null], [4,5,6]);
+-----------------------------------------------------+
| all_match((x, y) -> x < y, [1, 2, NULL], [4, 5, 6]) |
+-----------------------------------------------------+
|                                                NULL |
+-----------------------------------------------------+

select all_match((x,y) -> x < y, [1,2,8], [4,5,6]);
+--------------------------------------------------+
| all_match((x, y) -> x < y, [1, 2, 8], [4, 5, 6]) |
+--------------------------------------------------+
|                                                0 |
+--------------------------------------------------+

select all_match((x,y) -> x < y, [], []);
+------------------------------------+
| all_match((x, y) -> x < y, [], []) |
+------------------------------------+
|                                  1 |
+------------------------------------+

select all_match((x,y) -> x < y, null, [4,5,6]);
+---------------------------------------------+
| all_match((x, y) -> x < y, NULL, [4, 5, 6]) |
+---------------------------------------------+
|                                        NULL |
+---------------------------------------------+