Regular Expression (regex) Tutorial

Did you ever learn what ^(?i)(?<word>\p{L}+\d{2,4}(?:-\w+)?)(?=\s|$)(?:.*?\k<word>.*)+$ would ever do? Do you want to? I thought I would put together a document that was created almost a decade ago involving Regular Expressions (regex). If anyone is interested, you can view the tutorial:

• Regular Expression Tutorial pg1

• Different Regular Expression Engines pg 2

• Literal Characters pg 3

• Special Characters pg 4

• Non-Printable Characters pg 5

• First Look at How a Regex Engine Works Internally pg 6

• Character Classes or Character Sets pg 7

• The Dot Matches (Almost) Any Character pg 8

• Start of String and End of String Anchors pg 9

• Word Boundaries pg 10

• Alternation with the Vertical Bar or Pipe Symbol pg 11

• Optional Items pg 12

• Repetition with Star and Plus pg 13

• Grouping with Round Brackets pg 14

• Named Capturing Groups pg 15

• Unicode Regular Expressions pg 16

• Regex Matching Modes pg 17

• Possessive Quantifiers pg 18

• Understanding Atomic Grouping in Regular Expressions pg 19

• Understanding Lookahead and Lookbehind in Regular Expressions (Lookaround) pg 20

• Testing Multiple Conditions on the Same Part of a String with Lookaround pg 21

• Understanding the \G Anchor in Regular Expressions pg 22

• Using If-Then-Else Conditionals in Regular Expressions pg 23

• XML Schema Character Classes and Subtraction Explained pg 24

• Understanding POSIX Bracket Expressions in Regular Expressions pg 25

• Adding Comments to Regular Expressions: Making Your Regex More Readable pg 26

• Free-Spacing Mode in Regular Expressions: Improving Readability pg 27