Practice - Formal Definition and Syntax (Recursive Construction)
Practice Questions
Test your understanding with targeted questions
What does the regular expression ∅ represent?
💡 Hint: Think of it as having no possible options.
Write a regular expression for a single character 'b'.
💡 Hint: It's simply the character itself.
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Interactive Quizzes
Quick quizzes to reinforce your learning
What does the expression 'ϵ' represent?
💡 Hint: Think about what the empty string actually includes.
True or False: The expression a | b means match either 'a' or 'b'.
💡 Hint: Consider if 'or' means one of the options.
1 more question available
Challenge Problems
Push your limits with advanced challenges
Construct a regular expression that describes a string containing only the letters a to z, with lengths ranging from 1 to 5 characters.
💡 Hint: Consider using ranges to define the permissible characters and lengths.
Create a regex to match a valid email format: it must have an alphanumeric username followed by '@', then a domain.
💡 Hint: Think about components of emails and their general format.
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Reference links
Supplementary resources to enhance your learning experience.