Using replace function to replace value to one of value map using QGIS field calculator?

I kind of made a mistake, with a certain setting one column to a value map. Originnaly the "Regio Column' had text which consited of four specific value's (five if I count Null with it). To make thing simplier for field work, I decided to add a dropdown list, and for specific "numbering reason" of the object I gave each text a number, but in actuality they see only the text they need to choose. But something went wrong and it is kind of my own fault since I needed to replaced text. I cannot change this now.

Now because I have over 3000 records changing manualy those (centrum) and other values to the actual value of the value map choice by choosing down the dropdown list is kind of tedious. I tried to use the replace function but I cannot get it right. To illustrate see image below:

What I am doing wrong here?

Answer

You missed a comma after your field, it should be

replace("Regio", '(centrum)', '1')