incremental number at text string for use in calculated column

Question

I need to create a unique ID number of each new project in the follow format 00-0000-000000 where the middle four digits are a number that increments by one for each new project. I have a list called variables with a column called proj_number which holds a single entry which is incremented by workflow each time a new project site is requested. Here is my issue:

In order to increment the number it must be a number field which has compulsory formatting and won't stay in a four digit (0000) format so I need either

1. A way to increment a four digit string by 1 using a work flow or
2. A way of adding 00s to the number column so that is always four digits long.

any thoughts gratefully received.

Answer 1

KGlasier's approach works perfectly in my test list.

Answer 2

You could take a look at this article. It talks about padding numbers with leading zeroes which you may be able to modify with a calculated column.

Below is the general idea, slightly modified to your situation.

=CONCATENATE(
    [Column1],
    "-",
    REPT("0",4-LEN([Column2])),
    [Column2],
    "-",
    [Column3]
)

Column1 is the field of your first two characters. This could also be some formula if you need to derive it from a date field or some such.

Separate that with a dash. Now Column2 is the four digit integer you're looking for. We repeat the "0" string a few times (equal to 4 - length of your integer column), to add the necessary padding. Then add Column2 to the end of it.

Separate that with a dash and add your last 6-character string to the end.