AttributeError: 'QgsVectorLayer' object has no attribute 'fieldNameIndex'

Question

When I try to calculate a new field with:

idx = layer.fieldNameIndex(attributeName)

I receive the following error:

AttributeError: 'QgsVectorLayer' object has no attribute 'fieldNameIndex'

What´s the problem? I'm using QGIS 3.0.1 64x in Windows.

Please, do not forget about "What should I do when someone answers my question?" — Taras, Nov 19 '22 at 11:25

score 19 · Accepted Answer · edited Nov 19 '22 at 11:41

In PyQGIS 3

Use one of the following methods from the QgsFields class:

layer = iface.activeLayer()
layer_fields = layer.fields()
field_index = layer_fields.indexFromName("FIELD_NAME")

layer = iface.activeLayer()
layer_fields = layer.fields()
field_index = layer_fields.lookupField("FIELD_NAME")

layer = iface.activeLayer()
layer_fields = layer.fields()
field_index = layer_fields.indexOf("FIELD_NAME")

score 7 · Answer 2 · edited Nov 19 '22 at 11:37

7

You need to access it via the fieldNameIndex() method of the QgsVectorDataProvider class:

layer = iface.activeLayer()
idx = layer.dataProvider().fieldNameIndex(attributeName)

edited Nov 19 '22 at 11:37

Taras

answered Apr 18 '18 at 14:14

Joseph

How do you do that in the Python console? I'm a noob. – Novvier Apr 18 '18 at 16:28
@MarcoUscuchagua - Click on a layer and type layer = iface.activeLayer(). Then type idx = layer.dataProvider().fieldNameIndex("fieldName"). Theself` parameter is mainly used for plugins. – Joseph Apr 20 '18 at 09:15
The error remains. I think it is a error of QGIS and not of my layer. – Novvier Apr 20 '18 at 12:17
@MarcoUscuchagua - What error are you receiving? Is it the same error as in your question? – Joseph Apr 20 '18 at 12:34
Yes! The exactly error: image – Novvier Apr 20 '18 at 22:11
@MarcoUscuchagua - If you're using the Python Console, do not use self. – Joseph Apr 23 '18 at 09:51
1

I found the solution!! The problem was in the Quick Attribution plugin, its reinstallation solved the problem. Thanks @Joseph – Novvier Apr 24 '18 at 00:42
@MarcoUscuchagua - Glad you found a solution :) – Joseph Apr 26 '18 at 10:05