Hi,
I have a number of files that at some point or another have been tagged with track numbers and disc numbers in the format 1/12, 1/2, etc so that it includes the total number of tracks/discs. I am looking for a way to get these just to be a straightforward number.
Is this easily done with MP3Tag?
Yes.
Just define an action group with 2 actions inside (Menue->Actions->Actions or ALT-6):
Action
Type: Guess values
Source format: %track%
Guessing pattern: %track%/%dummy%
Action
Type: Guess values
Source format: %discnumber%
Guessing pattern: %discnumber%/%dummy%
Mark all files and apply the action group.
The same could be achieved with actions of the type
Format value for the respective field
Format string: $num(%fieldname%,2)
This would result in leading zeros if the discnumber or the tracknumber has only 1 digit.
If it is wanted, o.k.
True.
you may, of course, modify the expression to
$num(%fieldname%,1)
This leaves nothing but the first intelligeble number.
and is not universal because you have to filter the cases mit 2 digits and only 1 digit before applying the action.
That is amazing. To my experience the treatment of e.g.
$num('2016-03-10T04:38:00Z',1) leads to 2016 - the $num() function really only converts a string into a number and has the additional function to supply padding, if requested.
Shame on me. You are right. I was pretty sure because I tested it but maybe I am getting old. 
I was looking for this for so long! I love it <3