Variable Expression

The KNIME Variable Expression node enables generic manipulation of flow variables within KNIME workflows.

Flow Variables: Each expression is evaluated and the result is used to change an already existing or create a new flow variable. Flow variables can be accessed via $$["Flow Variable Name"] , or you can use the shorthand $$flow_variable_name , if the name does not contain any special characters nor spaces.

Operators : The expression language supports basic operators, namely arithmetic ( + , - , * , / float division, // integer division, ** exponentiation, % modulo), comparison ( < , <= , > , >= , = , != ), logical ( and , or , not ), string concatenation ( + ) and a special 'missing coalescing' operator ?? which sets a default value if the left operand is missing.

Functions: The variable expression node supports a wide range of functions which are available in a catalog on the right side of the editor.

AI Expression Assistance (Labs): If the KNIME AI Assistant (Labs) extension is installed, the button on the lower left of the code editor provides access to AI assisted expression generation and modification. Here you can enter commands in natural language and our expression assistant will replace or modify your current expression according to your prompt. The more precisely you describe what results you expect, the better the results will be. The AI will suggest modifications and show them to you in a diff-view (differences between your current expression on the left and the suggested expression on the right) which you can apply or query another response by entering a new or refined prompt.