Regular Expressions 101

^start of line

Negative Lookahead(?!.*[.-](?=[.-]))

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

Character Class[.-]

.the literal . (46₁₀ / 56₈ / 2E₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Positive Lookahead(?=[.-])

Character Class[.-]

.the literal . (46₁₀ / 56₈ / 2E₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Negated Character Class[^.-]

.the literal . (46₁₀ / 56₈ / 2E₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Character Class[a-z0-9.-]{1,61}

{1,61}matches between 1 and 61 characters from the set below:

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

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

.the literal . (46₁₀ / 56₈ / 2E₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Negated Character Class[^.-]

.the literal . (46₁₀ / 56₈ / 2E₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

$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.

Search reference

Regular Expression

^(?!.*[.-](?=[.-]))[^.-][a-z0-9.-]{1,61}[^.-]$

Test String
New

abc-123.xyz
abc123-.xyz 
123456789012345678901234567890123456789012345678901234567890123

1234567890123456789012345678901234567890123456789012345678901234

Regular Expression

Test StringNew

ExtractionProcessing...

Test String
New

Extraction
Processing...