Loading a style (.qml) via PyQGIS

Question

I want to load a (.qml) style file to a specific layer, I tried this:

layer = QgsProject.instance().mapLayersByName(layer_name)
if layer.wkbType() == QGis.WKBLineString:
    layer.loadNamedStyle('styles/lines.qml')
layer.triggerRepaint()

Also, I tried this:

layer = QgsProject.instance().mapLayersByName(layer_name)
if layer.geometryType() == QgsWkbTypes.LineGeometry:
    layer.loadNamedStyle('styles/lines.qml')
layer.triggerRepaint()

But I get this error:

if layer.wkbType() == QGis.WKBLineString:

# AttributeError: 'list' object has no attribute 'wkbType'

Answer 1

The method mapLayersByName() returns a list. To return a layer object you need to index the list to access its first element (assuming there is only one layer by that name in your project) e.g.

layer = QgsProject.instance().mapLayersByName(layer_name)[0]
if layer.geometryType() == 1:#Line geometry
    layer.loadNamedStyle('path\\to\\style_file.qml')