1. i206: Lecture 19: Regular Expressions, cont.
Marti Hearst
Spring 2012

2. Regex for Dollars No commas With commas With or without commas
\$[0-9]+(\.[0-9][0-9])?
With commas
\$[0-9][0-9]?[0-9]?(,[0-9][0-9][0-9])*(\.[0-9][0-9])?
With or without commas
\$[0-9][0-9]?[0-9]?((,[0-9][0-9][0-9])*| [0-9]*) (\.[0-9][0-9])?

3. Using Regex’s
Two basic operations that regular expressions are used for: searching and matching.
Searching: moving through a string to locate a sub-string that matches a given pattern,
Matching: testing a string to see if it conforms to a pattern.
After matching you might want to substitute in alternative strings, or split up the strings.

4. Regex in Python Python documentation on regular expressions
import re
result = re.search(pattern, string)
result = re.findall(pattern, string)
result = re.match(pattern, string)
Python documentation on regular expressions
Some useful flags like IGNORECASE, MULTILINE, DOTALL, VERBOSE
A nice tutorial:

5. Verbose Regex’s (allows for comments and multi-line expressions)
On input of: XXX,36346, , -1