24.1.6. Modeler tools

Conditional branch
Load layer into project
Raise exception
Raise warning
Rename layer
Save log to file
Set project variable
String concatenation

These tools are only available in the Graphical Modeler. They are not available in the Processing Toolbox.

24.1.6.1. Conditional branch 

Adds a conditional branch into a model, allowing parts of the model to be executed based on the result of an expression evaluation. Mostly by using tool dependencies to control the flow of a model.

Parameters

Label	名称	Type	Description
Field	`BRANCH`	[string]	Name of the condition
Field	`CONDITION`	[expression]	Expression to evaluate

Outputs

None.

Python code

Algorithm ID: native:condition

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.1.6.2. Load layer into project 

Loads a layer to the current project.

Parameters

Label	名称	Type	Description
Layer	`INPUT`	[layer]	Layer to load in the legend
Loaded layer name	`NAME`	[string]	Name of the loaded layer

Outputs

Label	名称	Type	Description
Layer	`OUTPUT`	[same as input]	The (renamed) loaded layer

Python code

Algorithm ID: qgis:loadlayer

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.1.6.3. Raise exception 

Raises an exception and cancels a model's execution. The exception message can be customized, and optionally an expression based condition can be specified. If an expression condition is used, then the exception will only be raised if the expression result is true. A false result indicates that no exception will be raised, and the model execution can continue uninterrupted.

Parameters

Label	名称	Type	Description
Message	`MESSAGE`	[string]	Message to display
Condition	`CONDITION`	[expression]	Expression to evaluate if true

Outputs

None.

Python code

Algorithm ID: native:raiseexception

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.1.6.4. Raise warning 

Raises a warning message in the log. The warning message can be customized, and optionally an expression based condition can be specified. If an expression condition is used, then the warning will only be logged if the expression result is true. A false result indicates that no warning will be logged.

Parameters

Label	名称	Type	Description
Message	`MESSAGE`	[string]	Message to display
Condition	`CONDITION`	[expression]	Expression to evaluate if true

Outputs

None.

Python code

Algorithm ID: native:raisewarning

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.1.6.5. Rename layer 

Renames a layer.

Parameters

Label	名称	Type	Description
Layer	`INPUT`	[layer]	Layer to rename
New name	`NAME`	[string]	The new name of the layer

Outputs

Label	名称	Type	Description
Layer	`OUTPUT`	[same as input]	The (renamed) output layer

Python code

Algorithm ID: native:renamelayer

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.1.6.6. Save log to file 

Saves the model's execution log to a file. Optionally, the log can be saved in a HTML formatted version.

Parameters

Label

名称

Type

Description

Use HTML

USE_HTML

[Boolean]

Default: False

Use HTML formatting

Outputs

Label	名称	Type	Description
File	`OUTPUT`	[string]	Destination of the log

Python code

Algorithm ID: native:savelog

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.1.6.7. Set project variable 

Sets an expression variable for the current project.

Parameters

Label	名称	Type	Description
Variable name	`NAME`	[string]	Name of the variable
Variable value	`VALUE`	[string]	Value to be stored

Outputs

None.

Python code

Algorithm ID: native:setprojectvariable

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.1.6.8. String concatenation 

Concatenates two strings into a single one in the Processing Modeler.

Parameters

Label	名称	Type	Description
Input 1	`INPUT_1`	[string]	First string
Input 2	`INPUT_2`	[string]	Second string

Outputs

Label	名称	Type	Description
Concatenation	`CONCATENATION`	[string]	The concatenated string

Python code

Algorithm ID: qgis:stringconcatenation

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.