How to fill fields with layer name in PyQGIS

Question

I have hundreds of shapefiles that I have added to a QGIS project. I am using QGIS 3.0.0. I have created a new text field for each of them named 'Enumertr' in PyQGIS and I need to populate this field in each of the shapefiles with the name of the respective layer. I have the below script, but it is bringing an error. I also need to adapt it to iterate through all of the layers in my QGIS project. I am relatively new to Python but am hoping using PyQGIS will save me a substantial amount of time if I can finalise this script.

from PyQt4.QtCore import QVariant
from qgis.core import QgsField, QgsExpression, QgsFeature
vl = iface.activeLayer()
vl.startEditing()
idx = vl.lookupField(‘Enumertr’)
e = QgsExpression (‘vl.name’)
e.prepare(vl.fields())
for f in vl.getFeatures():
    f[idx] = e.evaluate( f )
    vl.updateFeature( f )
vl.commitChanges()

Answer 1

You could use something like the following in the Python Console:

for layer in QgsProject.instance().mapLayers().values():
    with edit(layer):
        for feature in layer.getFeatures():
            feature.setAttribute(feature.fieldNameIndex('Enumertr'), layer.name())
            layer.updateFeature(feature)