regex101: PCRE (Legacy) Match Workspace

Non-Capturing Group(?:^|,)

1st Alternative^

^start of line

2nd Alternative,

,the literal , (44₁₀ / 54₈ / 2C₁₆)

Group 1([^,\r\n]+)

Negated Character Class[^,\r\n]+

+matches at least one character outside the set below:

,the literal , (44₁₀ / 54₈ / 2C₁₆)

\ra carriage return (ASCII 13)

\na line-feed (newline) character (ASCII 10)

\s*any whitespace character, repeated any number of times

,the literal , (44₁₀ / 54₈ / 2C₁₆)

Character Class[,\s]*

*matches any number of characters from the set below:

,the literal , (44₁₀ / 54₈ / 2C₁₆)

\sany whitespace character

Positive Lookahead(?=\1 (?![A-Za-zА-ЯЁа-яё]) )

\1the text saved by group 1

Negative Lookahead(?![A-Za-zА-ЯЁа-яё])

Character Class[A-Za-zА-ЯЁа-яё]

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

А-Яone character from А (1040₁₀) to Я (1071₁₀) (case sensitive)

Ёthe literal Ё (1025₁₀ / 2001₈ / 401₁₆) (case sensitive)

а-яone character from а (1072₁₀) to я (1103₁₀) (case sensitive)

ёthe literal ё (1105₁₀ / 2121₈ / 451₁₆) (case sensitive)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

X modifier: eXtra. A \ followed by a letter with no special meaning causes an error

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

Search reference

Regular Expression

(?:^|,)
([^,\r\n]+)
\s*,[,\s]*
(?=\1 (?![A-Za-zА-ЯЁа-яё]) )

Test String
New

Центральный федеральный округ,Москва
Центральный федеральный округ Москва,Москва
Центральный федеральный округ,Москва,Москва
Центральный федеральный округ,Москва ,Москва
Центральный федеральный округ,Великий Устюг , Великий Устюг
Центральный федеральный округ,Великий Устюг,Великий Устюгов

Regular Expressions 101

Regular Expression

Test String
New

Substitution
Processing...

Regular Expression

Test StringNew

SubstitutionProcessing...

Test String
New

Substitution
Processing...