Setting name of output layer PyQGIS

Question

The script below is to merge number of layers in a specific group, the output layer name is Merged. How can I change the name? I tried to change the output parameters but it's not working.

root = QgsProject.instance().layerTreeRoot()
group = root.findGroup("RL")
layers = [layer.layer()
for layer in group.children()] 
merged = processing.run("native:mergevectorlayers",\
{'LAYERS': layers, 'OUTPUT':"TEMPORARY_OUTPUT"})["OUTPUT"]
QgsProject.instance().addMapLayer(merged, False)
root.insertLayer(0, merged)
root = QgsProject.instance().layerTreeRoot()
group = root.findGroup("SL")
layers = [layer.layer()
for layer in group.children()]
merged = processing.run("native:mergevectorlayers",\
{'LAYERS': layers, 'OUTPUT':"TEMPORARY_OUTPUT"})["OUTPUT"]
QgsProject.instance().addMapLayer(merged, False)
root.insertLayer(0, merged)

• Matt: Just a tip, you don't need to use line endings ; with Python

Answer 1

You can use the QgsMapLayer.setName() function. Based on your script, you can do something along the lines of:

merged.setName("This is the new layer name")

• Ahmed Kamel: I write it at the end of the script but it gives me error
• fastest: What is the error message? Otherwise, I would suggest to put the command right after you have executed the processing algorithm (i.e., before calling addMapLayer())
• Jacqueline: what is the error? it works.
• Ahmed Kamel: I tried this and it's working ``` blockLayer = QgsProject.instance().mapLayersByName("Merged")[0] blockLayer.setName("SL Dozers")

Answer 2

In a comment you said "I tried this and it's working"

blockLayer = QgsProject.instance().mapLayersByName("Merged")[0] 
blockLayer.setName("SL Dozers")

This may not work if there should be more than one layer with the same name in your project. See my answer to a similar question for a failsafe way: https://gis.stackexchange.com/a/352267/10123

output = processing.run("native:mergevectorlayers",\
{'LAYERS': layers, 'OUTPUT':"TEMPORARY_OUTPUT"})["OUTPUT"]
createdlayer = QgsProject.instance().mapLayer(output)
createdlayer.setName('My shiny new beautiful layer') 

(Explanation: What is returned by the algorithm is a dictionary where you can find an id for the layer, then you can get and rename the layer using the unique id rather than the name)

• Ahmed Kamel: there is an error with "parmas" in the first line you typed
• MortenSickel: That is just whatever parameters you put onto the function, I rewrote it to use your example, hope this works