This node takes a list of user-defined rules and tries to match them to each row in the input table. If the first matching rule has a TRUE outcome, the row will be selected for inclusion. Otherwise (i.e. if the first matching rule yields FALSE ) it will be excluded. If no rule matches the row will be excluded. Inclusion and exclusion may be inverted, see the options below.

Each rule is represented by a row. 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 either TRUE or FALSE .

If no rule matches, the outcome is treated as if it was FALSE .

Columns are given by their names surrounded by $, numbers are given in the usual decimal representation. Note that strings must not contain (double-)quotes (for those cases use the following syntax: /Oscar Wilde's wisdom: "Experience is simply the name we give our mistakes."/ ). The flow variables are represented by $${ TypeCharacterAndFlowVarName }$$ . 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.

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

// This is a comment
$Col0$ > 0 => TRUE

When the values in Col0 are greater than 0, we select the row (if no previous rule matched with FALSE outcome).

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

You can combine conditions.

$Col0$ LIKE "Market Street*" AND 
    ($Col1$ IN ("married", "divorced") 
        OR $Col2$ > 40) => FALSE

With parentheses you can combine multiple conditions.

$Col0$ MATCHES $${SFlowVar0}$$ OR $$ROWINDEX$$ < $${IFlowVar1}$$ =>
    FALSE

The flow variables, table constants can also appear in conditions.

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

• ? =,<=,>= ?
• NaN =,<=,>= NaN