Regular Expressions 101

(?mi)applies the following effective flags to the remainder of the pattern: gmi

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

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

^start of line

Character Class[a-z]

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

Negative Lookahead(?!(?:.*\.){2})

Non-Capturing Group(?:.*\.){2}

{2}repeats the group contents below exactly 2 times:

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

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Negative Lookahead(?!(?:.* ){2})

Non-Capturing Group(?:.* ){2}

{2}repeats the group contents below exactly 2 times:

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

the literal (32₁₀ / 40₈ / 20₁₆)

Negative Lookahead(?!.*\.[a-z])

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

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[a-z]

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

Character Class[a-z. ]{3,18}

{3,18}matches between 3 and 18 characters from the set below:

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

.the literal . (46₁₀ / 56₈ / 2E₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

Character Class[a-z]

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

$end of line

Global pattern flags

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

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

(?mi)^[a-z](?!(?:.*\.){2})(?!(?:.* ){2})(?!.*\.[a-z])[a-z. ]{3,18}[a-z]$

New

Mr. Jackson
Mr Jackson
Mr Jack son
 Mr. Jackson
Mr. Jackson 
Mr. Jack.son
Mr.Jackson
Mr. Jac kson