QGIS 3 python 遍历图层并运行算法

Question

I'm attempting to loop through layers and run a processing algorithm on each layer but get an error with the input:

Code

feedback = QgsProcessingFeedback()

# Get current layers
layers = QgsProject.instance().mapLayers().values()

# Loop through layer and run algorithm
for layer in layers:
    processing.run("qgis:pointstopath", {'INPUT': layer, 'ORDER_FIELD': 'name', 'GROUP_FIELD': 'name','OUTPUT': layer+'.gpkg'},feedback)

Error

Traceback (most recent call last):
File "C:\OSGEO4~1\apps\Python37\lib\code.py", line 90, in runcode
exec(code, self.locals)
File "<input>", line 2, in <module>
File "C:/OSGEO4~1/apps/qgis-rel- 
dev/./python/plugins\processing\tools\general.py", line 105, in run
return Processing.runAlgorithm(algOrName, parameters, onFinish, feedback,
context)
File "C:/OSGEO4~1/apps/qgis-rel- 
dev/./python/plugins\processing\core\Processing.py", line 183, in 
runAlgorithm
raise QgsProcessingException(msg)
_core.QgsProcessingException: There were errors executing the algorithm.

How do you correctly parse the input layers from the map to the algorithm?

Answer 1

You don't need to use the 'value' method.

The right way is layers = QgsProject.instance().mapLayers()

The full code is:

feedback = QgsProcessingFeedback()

# Get current layers
layers = QgsProject.instance().mapLayers()

# Loop through layer and run algorithm
for layer in layers:
    processing.run("qgis:pointstopath", {'INPUT': layer, 'ORDER_FIELD': 'name', 'GROUP_FIELD': 'name','OUTPUT': layer+'.gpkg'},feedback)