Output to filename %_length%

The output at the tag columns for %_length% is minutes and seconds
separated by a : colon example 2:49.
When transferring %_length% to be included in the file name the colon :
converted to an underscore _ 2_49. Is there a way to change the underscore _
to nothing and have the output as 249?
Or is there a way to delete the last occurrence of the underscore _ in the file name?

Use the :mt_ttf: (Tag - Filename) with $regexp($regexp(%length%,'',.),^0+,)mins >>place other field/s here or before $replace<<

Will show up as 3.49mins. Just remove the optional things marked red if needs be.

That is correct, because the colon is a reserved character in the filesystem.
You can use the function $validate to define your own replacement character.

If you do not want to replace the default underline character at all, then you may use the function $replace to modify only the output of the %_length% system variable, ...
for example ...

$replace(%_length%,':',) ==> 0437 $replace(%_length%,':','m') ==> 04m37 $replace(%_length%,':','m')'s' ==> 04m37s '['$replace(%_length%,':','m')'s]' ==> [04m37s] $replace('('%_length%'s)',':','m') ==> (04m37s)

DD.20140219.2152.CET
DD.20140220.1500.CET

Sorry I should have included all I was doing. I have included it inside of one column called Bitrate
with the below expression and I believe that I can only use 1 replace function. But I could be wrong.

%_bitrate% $left(%_vbr%,1) $replace(%_mode%,Joint Stereo,JS,Stereo,S,Single Channel,M,Dual Channel,D) %_length%

After thinking about this I really don't need this in the file name and if I change my mind I can just delete the last occurrence of the _ anyway. And I can see this info in mp3tag and probably set foobar to see it also.

BTW I can not believe the lack of knowledge that people have on tagging their music lots of time they just dump all the info into comments, notes, description or even in the title area. Its driving me nutty.

Thank You for all of your help

Hello,

Maybe this helps:

To add the length and the Bitrate to my filenames I created the following action:

FormatValue
Field:
_Filename

Format string:
%artist% - %title% '['$left(%_length%,$sub($len(%_length%),2))m$right(%_length%,2)s']' '['%_bitrate%kBps']'

This results in a file name like:

ABBA - Thank you for the music [03m26s] [128kBps].mp3