Recall: Regex Syntax Reference

special chars

|	or
()	grouping
^	start
$	end

quantifiers

*	0 or more
+	1 or more
?	0 or 1
{min,max}	between min and max

character sets

[abcde]	one of those characters
[a-z]	a character from a through z
\d	digit
\s	whitespace

• The next exercise uses regular expressions. (lecture slides)

Exercise : Regular Expressions (by Zack Cava)

Write a regular expression (slides) that would match the following kinds of patterns. You can use the site Rubular to test your regex.

1. a student's letter grade such as A, B+, or D- (try it) (data)
2. a DNA sequence (string of any combination of A, C, G, T) (try it) (data)
3. a US ZIP code (try it) (data)
4. a credit card number, with optional dashes every 4 numbers (try it) (data)
5. a real number such as 3.14 or -42.8775 (try it) (data)

Regular Expressions, continued

6. a dollar amount of at least $100.00 (try it) (data)
7. a word with two or more vowels (A, E, I, O, or U) (try it) (data)
8. a string that starts with either 'q' or 's', and that also contains a double z ('zz') later within the same word (try it) (data)
9. a string that contains at least 5 vowels (a, e, i, o, or u) in a row (try it) (data)
10. a string that is at least 25 characters long (try it) (data)

Regular Expressions, continued

11. a string that ends with two or more occurrences of "?!", as in, "Huh?!?!" (try it) (data)
12. a valid amount for a US coin: 1, 5, 10, 25, or 50 cents (try it) (data)
13. an IP address, of the format 128.208.3.88 (accept any 3-digit numbers between the dots) (try it) (data)
14. a string that contains at least 3 words, each separated by one or more spaces (try it) (data)
15. a string that contains a quotation with "quote marks" around it (try it) (data)