Regular Expressions Basics

Marchete
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About Regular Expressions Basics

This course is designed as a fast, introductory course to Regular Expressions. Regular Expressions (aka Regex) are powerful tools used to perform very complex text searches with just a few lines of code.

Previous Knowledge:

Basic programming knowledge: Strings, Variables, Arrays, Loops, Functions. Regex searches can be used in almost any programming language. C# is used in this course, but only to store strings. You don't need any prior C# knowledge to complete the course.

Difficulty Level:

Intermediate.

Estimated Time:

60 minutes.

What will I learn?

Students will learn the most important features of Regular Expressions:

  • Reserved characters in Regex
  • Repetitions
  • Alternations
  • Capturing groups.

Why should I learn?

Regular Expressions are widely used in:

  • General text searches: Find specific text, based on complex patterns.
  • Input validation: Email/URL/IP validators.
  • Input parsing: Getting values from a long input string.
  • Web servers and proxies: Nginx and Apache use regex.
  • Log analyzers: Searching for patterns in log files.
  • Saving the day: https://xkcd.com/208/
XKCD Comic - Saving the day

But it's true. I saved my day by making a two line regex search for certain info in legal documents, reducing search times by 20x. The client was impressed at how smart my search was.

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