[CentralOH] Regular Expression and String Format Expression

[Mark Erbaugh]

I'm working on some code allows the user to configure certain input and output formats. For example, an account number consists of up to three integers (L1, L2 and L3). Using a regular expression, the user can configure how those three values are entered, i.e. 11-22-3333 or 3333.2211 or whatever they want.

Currently, I'm requiring the user to enter another string which is applied to Python's % (string format) operator to determine how to display an account number. The user is required to enter matching regular expression and string formats.

For example, if the format is 11-22-3333, the user could enter 

a regular expression of r'(?P<L1>\d\d)-(?P<L2>\d\d)-(?P<L3>\d\d\d\d)$'
and a format string of '%(L1)02d-%(L2)02d-%(L3)04d'

Is there a way to automatically create the string format expression from the regular expression or vice versa? 

Mark