/python-p3-regex-validations-lab

Primary LanguagePythonOtherNOASSERTION

RegEx Validations Lab

Learning Goals

  • Validate that strings match specific patterns using regular expressions.
  • Search for strings that match specific patterns using regular expressions.

Key Vocab

  • Regular Expression: a sequence of characters used to search for a pattern inside of a string.
  • Pattern: a description of sequences of characters that share certain traits with one another. Sequences do not need to be the same length or share any common characters to pattern match. Also called a filter.

Instructions

This is a test-driven lab. Run pipenv install to create your virtual environment and pipenv shell to enter the virtual environment. Then run pytest -x to run your tests. Use these instructions and pytest's error messages to complete your work in regex.py in the lib/ folder.

This lab is meant to give you experience with writing patterns for regular expressions and using the re module to check your pattern against different strings. Use regex101 to test your pattern as you work through the different strings.

  • Run pytest -x to execute the first test. This will check your name RegEx against the string "John Cena". This should be a match.
  • Once you've compiled a regular expression that matches this first string, run pytest -x again to check against the next string in line.
  • There will be several tests with valid names and invalid names. Your RegEx needs to discern between the two groups!
  • Repeat this process with the phone_number and email_address RegExes.

Once all of your tests are passing, commit and push your work using git to submit.

Hints

Regular expressions can be confusing and frustrating. You'll only get used to them with practice. That being said, there are some tools and tricks that will help you our along the way:

  • \w is shorthand for any word character: [A-Za-z0-9_]. \W is shorthand for anything outside of that range.
  • Similarly to \w, \S will match any non-whitespace character- though it includes characters not found in words as well. \s matches any single whitespace character.
  • Getting quotes, backslashes, and other operational characters into your regex requires that you lead with an escape character, the backslash (\).
  • Ignoring a specific set of characters (say, 'c', 'h', 'a', 'r', 's') can be accomplished with square brackets and carrots (^): [^chars].
  • Matching one pattern or another with the same regex can be accomplished with the | operator: r'hello|goodbye'.
  • regex101 provides a "Quick Reference" section in the bottom right corner that is very helpful for more tips and tricks along the way.

Resources