Regular Expressions 101

Explanation

Pro

^start of line

Negative Lookahead(?!.*'[A-Za-z]+')

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

'the literal ' (39₁₀ / 47₈ / 27₁₆)

Character Class[A-Za-z]+

+matches at least one character from the set below:

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

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

'the literal ' (39₁₀ / 47₈ / 27₁₆)

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

Character Class[A-Z]+

+matches at least one character from the set below:

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

Non-Capturing Group(?:['-]?[a-z]+)*

*repeats the group contents below any number of times:

Character Class['-]?

?matches at most one character from the set below:

'the literal ' (39₁₀ / 47₈ / 27₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Character Class[a-z]+

+matches at least one character from the set below:

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

Non-Capturing Group(?:\s*[a-z]*)*

*repeats the group contents below any number of times:

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

Character Class[a-z]*

*matches any number of characters from the set below:

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

$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.

26 tokens

^(?!.*'[A-Za-z]+')\s*[A-Z]+(?:['-]?[a-z]+)*(?:\s*[a-z]*)*$

New

John-andrew'andrew'john
 shouldn't work. But 
John-andrew'john-andrew'john

should work.

John-andrew'andrew'john
 shouldn't work. But 
John-andrew'john-andrew'john

should work.