Editing shp layers style simultaneously in QGIS?

Question

I have some polygons in a shp file that I need to change their line width. I head joined them in one group

Is there a way to change the line with for all of the layer in the group simultaneously and not one after the other?

Answer 1

With a little help from Python, we could set the border width for all layers in your "State" group to a specific value (e.g. 0.16 as shown in your image).

Try testing the following in the Python Console:

root = QgsProject.instance().layerTreeRoot()
state_group = root.findGroup("State")
border_width = 0.16

for layers in state_group.children():
    layer = layers.layer()
    symbols = layer.rendererV2().symbols()
    symbols[0].symbolLayer(0).setBorderWidth(border_width)
    layer.triggerRepaint()
    iface.legendInterface().refreshLayerSymbology(layer)