I wish to add a field in an attribute table that should work as a georeferencing key. It needs to take into consideration values from a series of fields. The last field is a housenumber and it contains from one to five digits (e.g. 2, 20, 20A, 200A, 200AB etc.) What shall I write in Field calculator to ensure that the above housenumbers becomes the following values in my new field: 002 020 020A 200A 200AB
So that the numbers are always represented with 3 digits (containing preceding zeros if necessary), and possible subsequent letters are kept?