Getting subtring from field value

is there a function to get a substring from a field and transfer it to a different field??

Here is an example that makes use of some string related functions of the Mp3tag script language.

Begin Actionsgroup masterp

Action #1
Actiontype 5: Format tag field
Field: FIELD_A
Formatstring: This÷is÷a÷string.

Action #2
Actiontype 5: Format tag field
Field: FIELD_B
Formatstring: $caps3($mid(%FIELD_A%,3,2)÷$left(%FIELD_A%,4)÷$mid(%FIELD_A%,2,3)÷$replace($right(%FIELD_A%,5),'.','?'))

Note: Replace one special character ÷ with one space character.
End Actionsgroup masterp (2 Actions)

DD.20090615.1052.CEST