Regular Expressions 101

Negative Lookahead(?!\s|digit-)

1st Alternative\s

\sany whitespace character

2nd Alternativedigit-

digit-the literal text digit- (case sensitive)

Group 1([0-9]{4})

Character Class[0-9]{4}

{4}matches exactly 4 characters from the set below:

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

Positive Lookahead(?=-digit|\.|\?|\s)

1st Alternative-digit

-digitthe literal text -digit (case sensitive)

2nd Alternative\.

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

3rd Alternative\?

\?the literal ? (63₁₀ / 77₈ / 3F₁₆)

4th Alternative\s

\sany whitespace character

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.

Search reference

Regular Expression

(?!\s|digit-)([0-9]{4})(?=-digit|\.|\?|\s)

 3400-digit
 5000 5000 
 6700?
digit-9134?
 7500.

$5000 
£5550 
#5550