Special Fields

Special functions are used to denote the specific fields under examination, or to generate a list of fields as input. For example, when deriving multiple fields at once, you should use @FIELD to denote "perform this derive action on the selected fields." Using the expression log(@FIELD) derives a new log field for each selected field.

Table 1. CLEM special fields
Function Result Description
@FIELD Any Performs an action on all fields specified in the expression context.
@TARGET Any When a CLEM expression is used in a user-defined analysis function, @TARGET represents the target field or "correct value" for the target/predicted pair being analyzed. This function is commonly used in an Analysis node.
@PREDICTED Any When a CLEM expression is used in a user-defined analysis function, @PREDICTED represents the predicted value for the target/predicted pair being analyzed. This function is commonly used in an Analysis node.
@PARTITION_FIELD Any Substitutes the name of the current partition field.
@TRAINING_PARTITION Any Returns the value of the current training partition. For example, to select training records using a Select node, use the CLEM expression: @PARTITION_FIELD = @TRAINING_PARTITION This ensures that the Select node will always work regardless of which values are used to represent each partition in the data.
@TESTING_PARTITION Any Returns the value of the current testing partition.
@VALIDATION_PARTITION Any Returns the value of the current validation partition.
@FIELDS_BETWEEN(start, end) Any Returns the list of field names between the specified start and end fields (inclusive) based on the natural (that is, insert) order of the fields in the data.
@FIELDS_MATCHING(pattern) Any Returns a list a field names matching a specified pattern. A question mark (?) can be included in the pattern to match exactly one character; an asterisk (*) matches zero or more characters. To match a literal question mark or asterisk (rather than using these as wildcards), a backslash (\) can be used as an escape character.
Note: This requires a string literal as an argument; it cannot use a nested expression to generate the argument.
@MULTI_RESPONSE_SET Any Returns the list of fields in the named multiple response set.