Unit 5 Regular expressions

Activity 1 Pattern matching fundamentals

Read about regular expressions and pattern matching in NLP.

Regular expressions (regex) are powerful pattern-matching tools essential for text processing in NLP. They allow you to search, extract, and manipulate text based on specific patterns rather than exact matches. Regex is particularly useful for preprocessing text, extracting entities, and cleaning messy data.

Core regex concepts for NLP:

• Literal matching: Finding exact text sequences
• Character classes: [a-z], [0-9], \d, \w, \s for matching categories
• Quantifiers: *, +, ?, {n,m} for repetition patterns
• Anchors: ^, $ for beginning and end of lines
• Groups: () for capturing and organizing matches
• Alternation: | for "or" conditions

Activity 2 Interactive regex tester

Test regular expression patterns in real-time.

Use this live regex tester to experiment with patterns and see matches highlighted instantly. Perfect for learning and debugging complex expressions.

Activity 3 Advanced regex techniques

Watch advanced pattern matching strategies for NLP.

This video (6 minutes) covers lookaheads, lookbehinds, non-greedy matching, and complex group patterns essential for sophisticated text processing tasks.

Activity 4 Text cleaning pipeline

Build a comprehensive text preprocessing tool using regex.

Create a multi-stage text cleaning pipeline that handles common preprocessing tasks for NLP applications.

Activity 5 Information extraction tool

Extract structured data from unstructured text using regex patterns.

Build a tool that can identify and extract various types of information from text documents.

Activity 6 Regex performance optimization

Learn to write efficient regex patterns for large-scale text processing.

This video (5 minutes) covers optimization techniques, avoiding catastrophic backtracking, and best practices for production NLP systems.

Activity 7 Pattern library builder

Create a reusable library of regex patterns for common NLP tasks.

Build and test a comprehensive collection of regex patterns that can be used across different NLP projects.