Regex expression with leading zero

Question

I'm rather new to regex expressions and need help with a simple expression. I'm using Pentaho for ETL (Replace in String transformation) and I have column values that I need to add leading zeros to and parse out text as part of the database import. So far I have been unable to add the leading zero.

The column is called Region and the values are "region 8", "region 10", "region 11". My regex expression is ['Region'] which will eliminate the region text but produces results = "8", "10", "11". I need values to produce "08", "10", "11". So all the single digit numbers must have leading zeros.

Answer 1

Use a look ahead in two steps:

Regex 1:   region (?=\d\D)
Replace 1: 0

Regex 2:   region (?=\d\d)
Replace 2: (nothing)

A look ahead is non-consuming, so you don't have to bother with back references etc.