Negated Classes [^abc] — Everything Except

Caret as the first character means 'not'

[^abc] matches any single character that is NOT a, b, or c. The caret ^ at the start of a class flips the meaning — it's now "any character except these."

This is genuinely one of the most useful tools in regex. "Match until you hit a quote" → [^"]*. "Skip everything that's not a digit" → [^0-9]+. "Take all non-whitespace" → [^\s]+ (or just \S+, lesson 7).

Negated classes match newlines (unlike .)

This is the gotcha. [^x] matches every character that isn't x, INCLUDING \n. The dot . stops at newlines without DOTALL; negated classes don't. So [^"]* will happily span multiple lines, while .* won't.

This is sometimes what you want, sometimes not. If you're parsing a quoted string that legitimately spans lines, [^"]* is correct. If you want "everything until a quote on the same line," use [^"\n]*.

The caret is only special in position 1

[a^b] is the literal class "a, caret, or b." Caret is only the negation operator when it's the very first character inside the brackets.

Code

Negated classes pattern·python

import re

# Match a quoted string body (between quotes)
re.findall(r'"([^"]*)"', 'name="Pippa" age="3"')
# ['Pippa', '3']

# Match anything that ISN'T whitespace
re.findall(r'[^\s]+', 'hello world\tand\nfoo')
# ['hello', 'world', 'and', 'foo']

# Negated class spans newlines
re.findall(r'[^x]+', 'abc\ndef\nxyz')
# ['abc\ndef\n']  — \n was happily included

# Caret in position 2+ is literal
re.findall(r'[a^b]', 'a^b^a')
# ['a', '^', 'b', '^', 'a']

Negated Classes [^abc] — Everything Except

Caret as the first character means 'not'

Negated classes match newlines (unlike .)

The caret is only special in position 1

Code

External links

Exercise

Progress

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