Regular Expressions 101

^start of line

Negative Lookahead(?!.*[^a-zA-Z0-9\s][^a-zA-Z0-9\s])

.*any character (except for line terminators), repeated any number of times

Negated Character Class[^a-zA-Z0-9\s]

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

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

0-9one character from 0 (48₁₀) to 9 (57₁₀)

\sany whitespace character

Negated Character Class[^a-zA-Z0-9\s]

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

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

0-9one character from 0 (48₁₀) to 9 (57₁₀)

\sany whitespace character

Negative Lookahead(?!.*(?:^| )[^a-zA-Z0-9\s](?!\S))

.*any character (except for line terminators), repeated any number of times

Non-Capturing Group(?:^| )

1st Alternative^

^start of line

2nd Alternative

the literal (32₁₀ / 40₈ / 20₁₆)

Negated Character Class[^a-zA-Z0-9\s]

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

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

0-9one character from 0 (48₁₀) to 9 (57₁₀)

\sany whitespace character

Negative Lookahead(?!\S)

\Sany non-whitespace character

\S+any non-whitespace character, repeated at least once

Non-Capturing Group(?: \S+)*

*repeats the group contents below any number of times:

the literal (32₁₀ / 40₈ / 20₁₆)

\S+any non-whitespace character, repeated at least once

$end of line

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

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

^(?!.*[^a-zA-Z0-9\s][^a-zA-Z0-9\s])(?!.*(?:^| )[^a-zA-Z0-9\s](?!\S))\S+(?: \S+)*$

New

#

#A
A#
A2
3A

test 4a test #A test
test 4a test # test

test#
#_

 *test

< >
<_
__

a_
a_
__
aa

#

#A
A#
A2
3A

test 4a test #A test
test 4a test # test

test#
#_

 *test

< >
<_
__

a_
a_
__
aa