Selecting layer by expression with two variables using PyQGIS

Question

I would like to filter a column coming from a layer with the command layer.selectByExpression().

I would like to leave the name of the column as a variable (not fixed). I made a conditions inside the column and its works very well, but I can't enter the column name as a variable.

That is the function which I am using:

layer.selectByExpression('\"column_name\"{}'.format(condition))

and here is my code:

class Layer_filter:
    
    def __init__(self, name_layer, name_column, condition):
        self.name_layer = name_layer
        self.name_column = name_column
        self.condition = condition
        layer = QgsProject.instance().mapLayersByName(self.name_layer)[0]
        iface.setActiveLayer(layer)
        layer.selectByExpression('\"column_name"{}'.format(self.condition), QgsVectorLayer.SetSelection)

Answer 1

I hope I got the gist of the question correctly. Please, try this:

layer = QgsProject.instance().mapLayersByName('layer')[0]

target_field = 'Type' #layer.attributeDisplayName(1)
condition = 'Type 2'

if target_field in layer.fields().names():
    layer.selectByExpression(f"\"{target_field}\"='{condition}'")

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References:

• Selecting features using expression with PyQGIS
• Getting field names of layer using PyQGIS