Filling attribute column with numbers 1-50 on repeat in QGIS

Question

I have a large file of several hundred thousand polygons. It's too many to have an individual colour, so I want to create a column of numbers to which I can assign a random colour. So how do I create a column in the attribute of numbers 1 to 50 on repeat?

Answer 1

If you want a number going from 1 to 50 and repeat, you can use the modulo % operator combined with the @id variable (older versions of QGIS can use $id instead) :

@id % 50 + 1

(the color can be directly randomized with QGIS expressions but that is not the OP question)