Rule Engine (Dictionary)

Applies rules from a rules table to a data table. The rules follow the Rule Engine rules, though for PMML RuleSets stricter rules apply (no column reference in the outcome, cannot use regular expressions, 3-valued logic). If no rules match, the default value specified in the PMML tab is used, or missing when no default value was specified.
It takes a list of user-defined rules from the second input port (from the selected column(s)) and tries to match them to each row in the input table. If a rule matches, its outcome value is added into a new column. The first matching rule in order of definition determines the outcome.

Each rule is represented by a row, new line characters are replaced by spaces, even in string constants. To add comments, start a line in a (condition) cell with // (comments can not be placed in the same line as a rule). Anything after // will not be interpreted as a rule. Rules consist of a condition part (antecedent), which must evaluate to true or false, and an outcome (consequent, after the => symbol) which is put into the new column if the rule matches.

The outcome of a rule may be any of the following: a string (between quotes " or /), a number, a boolean constant, a reference to another column or the value of a flow variable value. The type of the outcome column is the common super type of all possible outcomes (including the rules that can never match). If no rule matches, the outcome is a missing value unless a default value is specified.

Columns are given by their name surrounded by $, numbers are given in the usual decimal representation. Note that strings must not contain (double-) quotes. Flow variables are represented by $${TypeCharacterAndFlowVarName}$$. (Column references are not supported for PMML outputs.) The TypeCharacter should be 'D' for double (real) values, 'I' for integer values and 'S' for strings.

The logical expressions can be grouped with parentheses. The precedence rules for them are the following: NOT binds most, AND, XOR and finally OR the least. Comparison operators always take precedence over logical connectives. All operators (and their names) are case-sensitive.

The ROWID represents the row key string, the ROWINDEX is the index of the row (first row has 0 value), while ROWCOUNT stands for the number of rows in the table. (These are not available for PMML.)

Some example rules (each should be in one row):

// This is a comment
$Col0$ > 0 => "Positive"

When the values in Col0 are greater than 0, we assign Positive to the result column value (if no previous rule matched).

$Col0$ = "Active" AND $Col1$ <= 5 => "Outlier"

You can combine conditions.

$Col0$ LIKE "Market Street*" AND
    ($Col1$ IN ("married", "divorced")
        OR $Col2$ > 40) => "Strange"
$Col0$ MATCHES $${SFlowVar0}$$ OR $$ROWINDEX$$ < $${IFlowVar1}$$ =>
    $Col0$

With parentheses you can combine multiple conditions. The result in the second case comes from one of the columns.

$Col0$ > 5 => $${SCol1}$$

The result can also come from a flow variable.

The following comparisons result true (other values are neither less, nor greater or equal to missing and NaN values):

? =,<=,>= ?
NaN =,<=,>= NaN

Options

Dictionary mode

Choose how the rules table encodes the rules.

Rule: A single column contains the full rule expression including the outcome (e.g. "$Col$ > 0 => TRUE").
Condition and value: Two separate columns are used: one for the condition part of the rule and one for the outcome value.

Rule column

The column in the rules table that contains the full rule expressions (condition and outcome combined, e.g. "$Col$ > 0 => TRUE").

Condition column

The column in the rules table that contains the condition part of each rule (e.g. "$Col$ > 0").

Value column

The column in the rules table that contains the outcome value for each rule (e.g. "TRUE" or "FALSE").

Treat values starting with $ as references

When checked, values in the value column that start with $ will be treated as references (for example, column, flow variable, or table property references) rather than literal string values.

Output mode

Choose whether to append a new column with the outcome of the rules, or replace an existing column.

Append column: Append a new column with the rule outcome to the input table.
Replace column: Replace an existing column in the input table with the rule outcome.

Append column

Name of the newly appended column, which contains the outcome of the rules.

Replace column

The column to replace with the rule outcome.

Enable PMML RuleSet generation

When checked, PMML mode evaluation is used and fails if the input cannot be translated to PMML.

Hit selection

The method used to select the outcome when multiple rules match.

First hit: The outcome of the first matching rule will be used.
Maximal matching weighted sum: Select all matching rules, sum the weight for all outcomes, select the highest sum's outcome.
Highest matching weight: Select from all matching rules the highest weight (regardless of order) and use its outcome.

Default value/score

The default score/value to use when no rules matched.

Default rule confidence

The default confidence value to use when it is not specified by the confidence column.

Rule confidence column

Specifies confidence of the rules based on the values in the selected column.

Default rule weight

The default weight value to use when it is not specified by the weight column.

Rule weight column

Specifies weight values for the rules based on the values in the selected column.

Append confidence values

When checked, confidence values are computed and written into a new column in the output table.

Confidence column name

The name of the column to write confidence values into.

Provide statistics

When checked, recordCount (and if Validation column is selected, also nbCorrect) is computed for the PMML output.

Validation column

The column which contains the correct prediction for the input (test/validation) table. When <none> selected, no nbCorrect value will be computed.

Input Ports

: Input data
: Rules to apply

Output Ports

: Table containing the computed column
: Possibly missing PMML port containing the rules in PMML RuleSet format

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Plugin version: 5.12.0.v202606171353

On NodePit since: 2026-08-08

Last update: 2026-08-20

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