User-Defined Functions

User-defined functions are essential functions to be called within the stream processor or data access layers. These functions can be written in q/Python and are referenced by assigned name rather than function name. Below are the details of the API used to load, list, and search for user-defined functions.

.kxi.udfs.load

Load a UDF into memory

.kxi.udfs.load[name;package]
.kxi.udfs.load[name;package;version;force]

Parameters:

name	type	description	default
`name`	`string`	Name of the UDF to be loaded.	Required
`package`	`string`	Name of the package from which to load the UDF.	Required

options:

name	type	description	default
`version`	`string or ::`	Version of the package from which to load the UDF. Can also be `::` to use the latest version of the specified package.	`::`
`force`	`boolean`	Whether to load the UDF regardless of whether a UDF of the same name has been loaded previously from a differently versioned package.	`0b`

Returns:

type	description
`function`	User-defined function as a callable function.

Loads the file associated with a UDF in order to retrieve the User-Defined Function for use.

Load the UDF "my_udf" from the "ml" package

q).kxi.udfs.list.all[]
name function language file_path ..
-----------------------------------------------------------------------------..
"ml_udf" ".test.test_udf" ,"q" "test/test-packages/ml/1..
"py_udf"     "func"                         "py"     "test/test-packages/ml/1..
"map_udf" ".test.map_udf" ,"q" "test/test-packages/ml/1..
"filter_udf" ".test.filter_udf"             ,"q"     "test/test-packages/ml/1..
"merge_udf" ".test.merge_udf" ,"q" "test/test-packages/ml/1..
"myudf"      ".test.sub_namespace.test_udf" ,"q"     "test/test-packages/ml/2..
"my_udf" ".ml.testing.func" ,"q" "test/test-packages/ml/2..
"test_udf"   ".ml.sub_namespace.test_udf"   ,"q"     "test/test-packages/ml/2..
"myudf" ".test.sub_namespace.test_udf" ,"q" "test/test-packages/ml/2..
"my_udf"     ".ml.testing.func"             ,"q"     "test/test-packages/ml/2..
"test_udf" ".ml.sub_namespace.test_udf" ,"q" "test/test-packages/ml/2..
"test"       ".test.function"               ,"q"     "test/test-packages/test..
q).kxi.udfs.load["my_udf";"ml"]
{[table;params]
 1+table
 }

Load the UDF "test" from the "1.2.0" version of the "test" package

q).kxi.udfs.load["test";"test";"1.2.0"]
{[table;params]table+params`test}

Load a UDF multiple times

q)udf1:.kxi.udfs.load["test";"test";"1.1.0";.var.kw[`force; 1b]];
q)udf2:.kxi.udfs.load["test";"test";"1.1.0";.var.kw[`force; 1b]];

.kxi.udfs.list.all

List all UDFs defined at the path under KX_PACKAGE_PATH with udf symbol in a list

.kxi.udfs.list.all[]
.kxi.udfs.list.all[udfSyms]

Parameters:

name	type	description
`udfSyms`	`string[]`	Symbols for user-defined function e.g. ("udf"; "my_udf"; "myudf")

Returns:

type	description
`table`	Table containing all the UDFs defined under `KX_PACKAGE_PATH` which match the presented search criteria.

q)setenv[`KX_PACKAGE_PATH;"test/test-packages"]
q).kxi.udfs.list.all[]
name function language file_path ..
-----------------------------------------------------------------------------..
"ml_udf" ".test.test_udf" ,"q" "test/test-packages/ml/1..
"py_udf"     "func"                         "py"     "test/test-packages/ml/1..
"map_udf" ".test.map_udf" ,"q" "test/test-packages/ml/1..
"filter_udf" ".test.filter_udf"             ,"q"     "test/test-packages/ml/1..
"merge_udf" ".test.merge_udf" ,"q" "test/test-packages/ml/1..
"myudf"      ".test.sub_namespace.test_udf" ,"q"     "test/test-packages/ml/2..

.kxi.udfs.list.file

List all the UDFs defined in a specific file

.kxi.udfs.list.file[path]

Parameters:

name	type	description
`path`	`string`	Path to the file that is to be searched for UDFs. Can be an absolute or relative path.
`udfSym`	`string`	Symbol for user-defined function e.g. udf, my_udf, myudf, ...

Returns:

type	description
`table`	Table outlining all the UDFs defined within the specified file.

List a summary of all the UDFs defined within a specified file

q).kxi.udfs.list.file["test/test-packages/ml/1.0.0/ml.q";"udf"]
name function language file_path descrip..
-----------------------------------------------------------------------------..
"ml_udf" ".test.test_udf" ,"q" "test/test-packages/ml/1.0.0/ml.q" "Additi..

Parameters:

Name	Type	Description
file
udfSym

.kxi.udfs.list.folder

List all the UDFs defined in the files within a specific folder

.kxi.udfs.list.folder[path]

Parameters:

name	type	description
`path`	`string`	Path to the folder that is to be searched for UDFs. Can be an absolute or relative path.
`udfSym`	`string`	Symbol for user-defined function e.g. udf, my_udf, myudf, ...

Returns:

type	description
`table`	Table outlining all the UDFs defined within the files in the specified folder.

List a summary of all the UDFs defined within the files in a specified folder

q).kxi.udfs.list.folder["test/test-packages/ml";"udf"]
name function language file_path ..
-----------------------------------------------------------------------------..
"ml_udf" ".test.test_udf" ,"q" "test/test-packages/ml/1..
"py_udf"     "func"                         "py"     "test/test-packages/ml/1..
"map_udf" ".test.map_udf" ,"q" "test/test-packages/ml/1..
"filter_udf" ".test.filter_udf"             ,"q"     "test/test-packages/ml/1..
"merge_udf" ".test.merge_udf" ,"q" "test/test-packages/ml/1..
"myudf"      ".test.sub_namespace.test_udf" ,"q"     "test/test-packages/ml/2..
"my_udf" ".ml.testing.func" ,"q" "test/test-packages/ml/2..
"test_udf"   ".ml.sub_namespace.test_udf"   ,"q"     "test/test-packages/ml/2..
"myudf" ".test.sub_namespace.test_udf" ,"q" "test/test-packages/ml/2..
"my_udf"     ".ml.testing.func"             ,"q"     "test/test-packages/ml/2..
"test_udf" ".ml.sub_namespace.test_udf" ,"q" "test/test-packages/ml/2..

Parameters:

Name	Type	Description
path
udfSym

.kxi.udfs.list.search

List all UDFs defined at the path under KX_PACKAGE_PATH with udf symbol in a list

.kxi.udfs.list.search[name;package;version]
.kxi.udfs.list.search[name;package;version;udfSyms]

Parameters:

name	type	description
`name`	`string or ::`	Regex filter string used to search for specific UDF name patterns. Can also be `::` to include all UDF names.
`package`	`string or ::`	Regex filter string used to search for specific package name patterns. Can also be `::` to include all package names.
`version`	`string or ::`	Regex filter string used to search for specific package version patterns. Can also be `::` to include all package versions.
`udfSyms`	`string[]`	Symbols for user-defined function e.g. ("udf"; "my_udf"; "myudf")

Returns:

type	description
`table`	Table containing all the UDFs defined under `KX_PACKAGE_PATH` which match the presented search criteria.

List a summary of all UDFs defined under KX_PACKAGE_PATH which match the presented search criteria

q)setenv[`KX_PACKAGE_PATH;"test/test-packages"]
q).kxi.udfs.list.searchPrep[::;::;::]
name function language file_path ..
-----------------------------------------------------------------------------..
"ml_udf" ".test.test_udf" ,"q" "test/test-packages/ml/1..
"py_udf"     "func"                         "py"     "test/test-packages/ml/1..
"map_udf" ".test.map_udf" ,"q" "test/test-packages/ml/1..
"filter_udf" ".test.filter_udf"             ,"q"     "test/test-packages/ml/1..
"merge_udf" ".test.merge_udf" ,"q" "test/test-packages/ml/1..
"myudf"      ".test.sub_namespace.test_udf" ,"q"     "test/test-packages/ml/2..
"my_udf" ".ml.testing.func" ,"q" "test/test-packages/ml/2..
"test_udf"   ".ml.sub_namespace.test_udf"   ,"q"     "test/test-packages/ml/2..
"myudf" ".test.sub_namespace.test_udf" ,"q" "test/test-packages/ml/2..
"my_udf"     ".ml.testing.func"             ,"q"     "test/test-packages/ml/2..
"test_udf" ".ml.sub_namespace.test_udf" ,"q" "test/test-packages/ml/2..
"test"       ".test.function"               ,"q"     "test/test-packages/test..

Search for all UDFs associated with the ml package

q)setenv[`KX_PACKAGE_PATH;"test/test-packages"]
q).kxi.udfs.list.searchPrep[::;"ml";::]
name function language file_path ..
-----------------------------------------------------------------------------..
"ml_udf" ".test.test_udf" ,"q" "test/test-packages/ml/1..
"py_udf"     "func"                         "py"     "test/test-packages/ml/1..
"map_udf" ".test.map_udf" ,"q" "test/test-packages/ml/1..
"filter_udf" ".test.filter_udf"             ,"q"     "test/test-packages/ml/1..
"merge_udf" ".test.merge_udf" ,"q" "test/test-packages/ml/1..
"myudf"      ".test.sub_namespace.test_udf" ,"q"     "test/test-packages/ml/2..
"my_udf" ".ml.testing.func" ,"q" "test/test-packages/ml/2..
"test_udf"   ".ml.sub_namespace.test_udf"   ,"q"     "test/test-packages/ml/2..
"myudf" ".test.sub_namespace.test_udf" ,"q" "test/test-packages/ml/2..
"my_udf"     ".ml.testing.func"             ,"q"     "test/test-packages/ml/2..
"test_udf" ".ml.sub_namespace.test_udf" ,"q" "test/test-packages/ml/2..

Search for all UDFs that start with the letter named "m"

q)setenv[`KX_PACKAGE_PATH;"test/test-packages"]
q).kxi.udfs.list.search["m*";::;::]
name function language file_path ..
-----------------------------------------------------------------------------..
"ml_udf" ".test.test_udf" ,"q" "test/test-packages/ml/1...
"map_udf"   ".test.map_udf"                ,"q"     "test/test-packages/ml/1...
"merge_udf" ".test.merge_udf" ,"q" "test/test-packages/ml/1...
"myudf"     ".test.sub_namespace.test_udf" ,"q"     "test/test-packages/ml/2...
"my_udf" ".ml.testing.func" ,"q" "test/test-packages/ml/2...
"myudf"     ".test.sub_namespace.test_udf" ,"q"     "test/test-packages/ml/2...
"my_udf" ".ml.testing.func" ,"q" "test/test-packages/ml/2...