RegEx XIV: Character Sets

A Character Set will match any characters within a pair of brackets [ ] . You can specify a range of characters by using a hyphen.

[abcd] == [a-d]

If the hyphen appears as the first or last character then it is considered a literal hyphen.

txt = "non-profit"
pattern = "[abc-]"

re.findall(pattern, txt) ➞ ["-"]

You can also use character classes in a character set.

[a-zA-Z0-9_] == [\w]

Write the regular expression that will match an "x" followed by two hexadecimal digits. A hexadecimal digit can be either one of the 10 decimal digits (0 to 9) or a letter from A to F.

Examples

txt1 = "Exception 0xAF"
txt2 = "Exception 0xD3"
txt3 = "Exception 0xd3"
txt4 = "Exception 0xZZ"
pattern = "yourregularexpressionhere"

re.findall(pattern, txt1) ➞ ["xAF"]
re.findall(pattern, txt2) ➞ ["xD3"]
re.findall(pattern, txt3) ➞ []
re.findall(pattern, txt4) ➞ []

Notes

• You don't need to write a function, just the pattern.
• Do not remove import re from the code.
• You can find all the challenges of this series in my Basic RegEx collection.