Python Edit Variable

KNIME Python nodes version 3.7.0.v201811291930 by KNIME AG, Zurich, Switzerland

Allows execution of a Python script in a local Python installation. The path to the Python executable has to be configured in Preferences → KNIME → Python. This node supports Python 2 and 3. It also allows to import Jupyter notebooks as Python modules via the knime_jupyter module that is part of the Python workspace.

Options

Script

Editor

The script in the editor panel in the center will be executed to generate this node's output. "Execute script" will execute the full script while "Execute selected lines" will only execute the currently selected part of the script.

The editor optionally provides autocompletion (CTRL + Space) if the Python module jedi is installed.

Flow variables

The pane on the left side of the editor panel lists the available flow variables. A double click on a flow variable will insert the corresponding identifier at the current cursor position in the editor panel.

Workspace

The pane on the right side of the editor panel is the workspace and lists the currently defined identifiers in the running Python instance. "Reset workspace" will remove the output of all past script executions.

Console

The console under the editor panel displays standard output, standard error, or other information.

Row limit (dialog)

Unused in this node.

Use python version

Allows to choose the python version that should be used for executing the kernel. Available installations can be checked under Preferences → KNIME → Python.

Missing values (Int, Long)

By default, Int and Long columns containing missing values are converted to doubles in Python, because doubles are the only numeric type containing a built-in missing value representation (NaN). Converting longs to doubles, however, introduces imprecision. The conversion may be avoided by replacing missing values with so-called sentinel values. To convert missing values to sentinel values before script execution, check the first option, to convert sentinel values back to missing values after script execution, check the second option. To select a sentinel value, click on MIN_VAL (the smallest possible value for the column's data type), MAX_VAL (the largest possible value for the column's data type), or a manually enter an integer in the text field.

Rows per chunk

Large tables are broken into chunks when they are transferred between Python and Java. This option controls how many rows are included in each chunk. The default value is intended for tables containing few columns having numeric types. If larger data types like images or text are transferred, a single chunk may exceed the maximum allowed buffer size. In this case lowering the value of this parameter helps getting reasonably sized chunks.

Templates

Create from editor...

Clicking on this button creates a new template based on the script in the editor panel of the script tab.

Note: User defined templates can be found in the folder: knime-workspace/.metadata/knime/sourcecode-templates/python-variables

Remove selected

Clicking on this button removes the selected template.

Note: Templates provided by plugins cannot be removed.

Apply selected

Replaces the script in the editor panel of the script tab with the selected template.

Input Ports

The input variables. In the Python script it is available as dictionary under the name flow_variables .

Output Ports

The output variables. This is the content of the variable flow_variables after the execution of the script.

Views

Standard output

The text sent by Python to the standard output, during the execution of this node.

Error output

The text sent by Python to the error output, during the execution of this node.

Best Friends (Incoming)

• Python Edit Variable (13 %) Manipulator
• CSV Writer (11 %) SinkStreamable
• String Input (8 %) QuickForm
• Create File Name (7 %) Other
• Table Row to Variable (7 %) Other
• Table Column to Variable (5 %) Other
• Java Edit Variable (simple) (5 %) Manipulator
• Single Selection (5 %) QuickForm
• Flow Variable IF Switch (Flow Variable Value) (3 %) Manipulator
• Table Row to Variable (3 %) Other
• Table Row To Variable Loop Start (3 %) LoopStart
• String Manipulation (Variable) (3 %) Manipulator
• Download (2 %) Other
• URL to File Path (Variable) (2 %) Manipulator
• Table Row To Variable Loop Start (2 %) LoopStart
• CSV Reader (2 %) Source
• CSV Writer (2 %) SinkStreamable
• Extract Context Properties (2 %) Source
• File Reader (2 %) SourceStreamable
• Counting Loop Start (2 %) LoopStart
• CASE Switch Variable (End) (2 %) Manipulator
• CASE Switch Variable (End) (2 %) Manipulator
• Merge Variables (2 %) Other
• Merge Variables (2 %) Other
• Excel Writer (XLS) (2 %) Sink
• Boolean Input (2 %) QuickForm
• Integer Input (2 %) QuickForm
• String Input (2 %) QuickForm
• Flow Variable IF Switch (Flow Variable Value) (< 1 %) Manipulator
• Column List Loop Start (< 1 %) LoopStart
• Column Filter (< 1 %) ManipulatorStreamable
• Column Splitter (< 1 %) ManipulatorStreamable
• CASE Switch Variable (Start) (< 1 %) Manipulator
• Don't Save Start (< 1 %) ScopeStart
• Python Source (< 1 %) Source
• String Input (legacy) (< 1 %) QuickFormDeprecated
• Show all 36 recommendations

Best Friends (Outgoing)

• Python Edit Variable (8 %) Manipulator
• Flow Variable IF Switch (7 %) Manipulator
• Java Edit Variable (6 %) Manipulator
• GET Request (6 %) ManipulatorStreamable
• Variable to Table Column (4 %) OtherStreamable
• Variable Loop End (4 %) LoopEnd
• IF Switch (4 %) Manipulator
• Python Script (1⇒1) (4 %) Manipulator
• CSV Writer (3 %) SinkStreamable
• Row Filter (3 %) ManipulatorStreamable
• Python Source (3 %) Source
• Create File Name (2 %) Other
• SQL Inject (2 %) Other
• Database Table Selector (2 %) Source
• List Files (2 %) Source
• Decision Tree Learner (2 %) Learner
• Create Temp Dir (2 %) Other
• MySQL Connector (2 %) Source
• FileLoader (1 %) 
• Create Directory (1 %) Other
• Breakpoint (1 %) Manipulator
• Try (Variable Ports) (1 %) ScopeStart
• Table Row to Variable (1 %) Other
• Variable to Table Row (1 %) Other
• CSV Reader (1 %) Source
• Database Reader (1 %) Source
• Database SQL Executor (1 %) Manipulator
• File Reader (1 %) SourceStreamable
• Loop End (1 %) LoopEnd
• String To Number (1 %) ManipulatorStreamable
• Pivoting (1 %) Manipulator
• String Replace (Dictionary) (1 %) ManipulatorStreamable
• Rule-based Row Filter (1 %) ManipulatorStreamable
• Rule Engine Variable (1 %) Manipulator
• CASE Switch Variable (Start) (1 %) Manipulator
• End IF (1 %) Manipulator
• Interactive Table (1 %) Visualizer
• Parallel Chunk Start (1 %) LoopStart
• Math Formula (1 %) ManipulatorStreamable
• Excel Writer (XLS) (1 %) Sink
• Text Output (1 %) QuickForm
• File Chooser (1 %) QuickForm
• String Input (1 %) QuickForm
• Python Learner (1 %) LearnerDeprecated
• R Snippet (1 %) Manipulator
• Create Collection Column (1 %) ManipulatorStreamable
• Variable to Table Row (1 %) Other
• CSV Writer (1 %) SinkStreamable
• Variable Loop End (1 %) LoopEnd
• Merge Variables (1 %) Other
• Date&Time Input (1 %) QuickForm
• Python Source (1 %) Source
• IDFilter (< 1 %) Manipulator
• SSH Connection (< 1 %) Source
• Column Rename (Regex) (< 1 %) ManipulatorStreamable
• Rule-based Row Splitter (< 1 %) ManipulatorStreamable
• Merge Variables (< 1 %) Other
• Send Email (< 1 %) Other
• WrappedNode Output (< 1 %) 
• Keras Network Reader (< 1 %) Source
• Explorer Writer (< 1 %) Sink
• Excel Reader (XLS) (< 1 %) SourceStreamable
• Single Selection (< 1 %) QuickForm
• Feature Calculator (BETA) (< 1 %) Manipulator
• Image Writer (< 1 %) 
• Wait... (< 1 %) Manipulator
• File Reader (< 1 %) SourceStreamable
• Row Filter (< 1 %) ManipulatorStreamable
• SQLite Connector (< 1 %) Source
• External Tool (Labs) (< 1 %) Other
• Show all 70 recommendations

Update Site

To use this node in KNIME, install KNIME Python nodes from the following update site: