Regex Tutorial 2: Repeat This, Repeat That

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Let's Avoid Being Redundant!

Regular Expressions can save you a lot of time, by describing complicated patterns that would be ridiculous to search documents for with a standard Search and Replace.

Repeat Operators

Symbol	Quantity	Example
+	One or more	Regex Captures Ignores "w+" "w", "wwwww", "wkd", "switch" "123", "mango", "smiley_faces", ""
*	Zero or more	Regex Captures Ignores "a*" "aab", "ab", "b", "LotsOfStuff", "" NO CASES
?	one or zero	Regex Captures Ignores "2?" "2", "a", "2a", "a2" "22", "0122", "a22b"

Practice Makes Perfect

Try and create the simplest regular expression to identify each text case below! Feel free to comment your answers. FYI: We are taking baby steps so if this is too easy (which it very well may be!) then feel free to skip this exercise.

1. aaabbbbccccc
2. knee
3. cabbage
4. 22nd street

Answers to these questions will be in Regex Tutorial #3.

• Regex Tutorial 1: Literal Text
• Regex Tutorial 2: Repeat This, Repeat that
• Regex Tutorial 3: Phone Nums