I have this attribute table:

enter image description here

I want to run a script for labelling:


for i in range(len(parametros)):
    if ID_sprof[i]==ID_sprof[i-1]:

This is a try of labeling the Profs of the next attribute together with the previous one. for example, considering that SO-31 has 3 Prof, I wanted one labelling like:

0,6 1,6 3,0

This is a resume of what I'm trying. I know this doesn't work in an expression. But this can be done by making some changes and defining a function in the expression editor.

This is just an example how I could access the information of another atribute to put in the other, but I know it doesn't work.

  • What GIS software are you using?
    – PolyGeo
    Commented May 22, 2023 at 20:12

1 Answer 1


For QGIS, use this expression:

array_to_string(array_agg(Prof, group_by:=ID_sprof))

You can add an optional argument between the second last and the last closing bracket ) to define (a) delimiter character(s) like this: delimiter:=' ' - what is inside the single quotes ' (here: a space enter code here) will be used as a delimiter. Use \n to insert a linebreak and get a separate row for each value.

  • Do you know where can i learn more about this?
    – Cortod
    Commented May 23, 2023 at 11:23
  • I'm trying to use that inside a function, when i run the function it goes well. But in the "expression" it acuses 'array_to_string' is not defined. Is it a native expression in qgis? When i just put the expression directly in the "expression" it works
    – Cortod
    Commented May 23, 2023 at 11:30
  • Documentation for QGIS expressions: docs.qgis.org/latest/en/docs/user_manual/expressions/… array_to_string() should work in newer QGIS versions.
    – Babel
    Commented May 23, 2023 at 12:39
  • Please, could you see my other question? gis.stackexchange.com/questions/460202/…
    – Cortod
    Commented May 23, 2023 at 17:06

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