I created a grid of hexagons and kept only the hexagons in a circle. In effect many hexagon-ids are missing and the remaining ones start at 1409.
I want them to be numbered consecutively in a logic way starting with 1 (top to bottom, left to right); i. e. 1409 should be 1, 1410 should be 2 ... 1495 should be 9, 1496 should be 10 ...
The attempt to use the expression
@row_number in the field calculator as suggested by this post: Filling column with consecutive numbers in QGIS used the Feature ID + 1 for the new value, as can be seen in the column 'test'.
From the list of functions (https://docs.qgis.org/testing/en/docs/user_manual/expressions/functions_list.html#functions-list) I understand that it should take the row-number instead, which would result in the exact sequence I desire.