QGIS 3 batch processing - INPUT value not correct when autofill

Question

I want to batch process with Clip function (also problem with any other). I have several input layers. I would like to autofill the output Clipped parameter with name of the input feature and _clipped suffix, such as in this example:

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The Expression String Builder acts oddly when I use @INPUT parameter, there is a name of the input feature along with some weird memory address or something.

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Why does this happen with the INPUT layer name? Where do I find the name without the odd suffix?

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I found out I can go around this when I tinker with the string a bit like so:

string_to_array(@INPUT,'_')[0]

Then I get:

enter image description here

However, what if the name itself contain underscores?

• John: If you use OUTPUT instead will that work?

Answer 1

That weird string is not a memory address, but the layer's id. You can use the following expression to construct INPUTLAYERNAME_clipped string. And no need string_to_array(@INPUT,'_')[0].

layer_property( @INPUT, 'name' ) + '_clipped'

layer_property(@INPUT, 'name') returns the layer name. If you need the layer source file name, use this:

base_file_name( layer_property( @INPUT, 'source' ) ) + '_clipped'

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• janchytry: Thanks! This is a good workaround a partly offers a solution. I wrote it earlier here as a Q&A style but it was deleted by the moderator as apparently a new question... Nevertheless, how comes that you don't get to acquire base file name in the query builder?
• Kadir Şahbaz: @janchytry Do you need the input file name instead of layer name?
• janchytry: Not exactly in this case, but often I do.
• Kadir Şahbaz: @janchytry I see, I've added how to get file name.
• janchytry: Thanks, that's an nice combination of functions I haven't known about.