Regular Expressions 101

Explanation

Pro

^start of line

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[xX]

xthe literal x (120₁₀ / 170₈ / 78₁₆) (case sensitive)

Xthe literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive)

Negative Lookahead(?!0+$)

0+the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated at least once

$end of line

Character Class[0-9a-fA-F]+

+matches at least one character from the set below:

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

a-fone character from a (97₁₀) to f (102₁₀) (case sensitive)

A-Fone character from A (65₁₀) to F (70₁₀) (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.

25 tokens

^0[xX](?!0+$)[0-9a-fA-F]+$

New

Invalid:
0x0
0x00
0x00000

Valid:

0x01
0x001
0x010

Invalid:
0x0
0x00
0x00000

Valid:

0x01
0x001
0x010