i am looking for a regular expression to sort chapters of a contract. Therefore i want to transform this chapter numbering to a 2-digit format "dd.dd.dd". Chapters are e.g.:

1.
1.2.1
...
2.10.4

Chapter numbering:

• 1 - 3 digit sections possible
• each section can have 1 or 2 digits
• dots are optional

My way:

• regex first digits: "\d \."
• regex second digits: "\.\d \.?"
• third digits are extracted with a split() function.
• i then assemble the 3 sections to a 2-digit-format (e.g. 02.10.04).

Problem:

• my solution seems not very safe. Because sometimes a dot is used after a digit section, sometimes it is not.
• maybe there is an easier way to simply "format"

Thanks for your support!

Regards, Fabian

CodePudding user response：

You may try the following find and replace, in regex mode:

Find:    (?<=\.|^)(\d)(?=\.|$)
Replace: 0$1

This regex pattern will capture all single digit path values which are sandwiched on both sides by either dots, or the start/end of the string. The replacement prepends a leading zero to make the digits have a width of two. Here is a demo showing that the logic is working.