Negated Shorthands — \D \W \S

~5 min · shorthand, negation

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Capital letter flips the meaning

Every shorthand has a capital-letter inverse:

\D — NOT a digit. Same as [^\d].
\W — NOT a word character. Same as [^\w].
\S — NOT whitespace. Same as [^\s].

That's the whole rule. Lowercase = the set, uppercase = the complement.

Real-world uses

\D+ is great for splitting: re.split(r'\D+', '2026-05-04') gives ['2026', '05', '04']. The non-digits between are eaten as the delimiter.

\S+ is a clean way to grab "runs of non-whitespace" — tokens, URLs, file paths.

\W is useful for finding word boundaries you control more tightly than \b can express.

Same Unicode caveats apply

Whatever flavor / flag controls the lowercase form controls the uppercase too. Python 3 default makes \D exclude every Unicode digit, not just ASCII 0-9.

Code

Negated shorthand patterns·python

import re

# Split on non-digits — extract numbers from a date
re.split(r'\D+', '2026-05-04')
# ['2026', '05', '04']

# Grab non-whitespace tokens
re.findall(r'\S+', 'hello world  \tfoo\nbar')
# ['hello', 'world', 'foo', 'bar']

# Find non-word characters (punctuation, symbols)
re.findall(r'\W', 'hello, world! 안녕?')
# [',', ' ', '!', ' ', '?']  — depends on Unicode mode

External links

Python re.split

Exercise

Take a messy string like ' apple , banana ; cherry ' and use one regex split to get a clean list ['apple', 'banana', 'cherry']. Hint: combine \W+ with strip().

Progress

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← PreviousShorthand Classes — \d \w \s Next →Escaping Special Characters — When and How

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