Regular Expressions Challenges (freeCodeCamp)

What is Regular Expressions?

According to freeCodeCamp, regular expressions are special strings that represent a search pattern. Also known as "regex" or "regexp", they help programmers match, search, and replace text. Regular expressions can appear cryptic because a few characters have special meaning. The goal is to combine the symbols and text into a pattern that matches what you want, but only what you want. This section will cover the characters, a few shortcuts, and the common uses for writing regular expressions.

Ordered Lessons & Answers

1. Using the Test Method
2. Match Literal Strings
3. Match a Literal String with Different Possibilities
4. Ignore Case While Matching
5. Extract Matches
6. Find More Than the First Match
7. Match Anything with Wildcard Period
8. Match Single Character with Multiple Possibilities
9. Match Letters of the Alphabet
10. Match Numbers and Letters of the Alphabet
11. Match Single Characters Not Specified
12. Match Characters that Occur One or More Times
13. Match Characters that Occur Zero or More Times
14. Find Characters with Lazy Matching
15. Find One or More Criminals in a Hunt
16. Match Beginning String Patterns
17. Match Ending String Patterns
18. Match All Letters and Numbers
19. Match Everything But Letters and Numbers
20. Match All Numbers
21. Match All Non-Numbers
22. Restrict Possible Usernames
23. Match Whitespace
24. Match Non-Whitespace Characters
25. Specify Upper and Lower Number of Matches
26. Specify Only the Lower Number of Matches
27. Specify Exact Number of Matches
28. Check for All or None
29. Positive and Negative Lookahead
30. Check For Mixed Grouping of Characters
31. Reuse Patterns Using Capture Groups
32. Use Capture Groups to Search and Replace
33. Remove Whitespace from Start and End