mapLayersByName(Qstring)

mapLayer(QString)

def selectLayerByOriginalName(tablename):
    # return layers whose orininal names start with 'tablename'
    llist = []
    for l in QgsMapLayerRegistry.instance().mapLayers().values():
        if tablename in l.id():
           if l.id().index(tablename) == 0:
               llist.append(lyr)
    return llist

def get_layer_source_table_name(self, layer):
        """ Get table or view name of selected layer """

        if layer is None:
            return None

        uri_table = None
        uri = layer.dataProvider().dataSourceUri().lower()
        pos_ini = uri.find('table=')
        pos_end_schema = uri.rfind('.')
        pos_fi = uri.find('" ')

        if pos_ini != -1 and pos_fi != -1:
            uri_table = uri[pos_end_schema + 2:pos_fi]

        return uri_table