Regular Expressions 101

1st Alternative(?<![a-zA-Z]{2})(?<=[a-zA-Z]{1})[ ]+(?=[a-zA-Z] |.$)

Negative Lookbehind(?<![a-zA-Z]{2})

Character Class[a-zA-Z]{2}

{2}matches exactly 2 characters from the set below:

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

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

Positive Lookbehind(?<=[a-zA-Z]{1})

Character Class[a-zA-Z]{1}

{1}matches one character from the set below:

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

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

Character Class[ ]+

+matches at least one character from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

Positive Lookahead(?=[a-zA-Z] |.$)

1st Alternative[a-zA-Z]

Character Class[a-zA-Z]

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

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

the literal (32₁₀ / 40₈ / 20₁₆)

2nd Alternative.$

.any Unicode character (except for line terminators)

$end of line

2nd Alternative(?<=\p{Han}) +

Positive Lookbehind(?<=\p{Han})

\p{Han}characters whose Script property is Han

+the literal (32₁₀ / 40₈ / 20₁₆) , repeated at least once

Global pattern flags

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

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

u modifier: unicode. Treats the pattern and subject as UTF-16

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?<![a-zA-Z]{2})(?<=[a-zA-Z]{1})[ ]+(?=[a-zA-Z] |.$)|(?<=\p{Han}) +

V e  r y calm', 'Keen and a n a l y t i c a l',
'R a s h and careless', 'Always joyful', '你 好', '黑 石  公 司'