Regular Expressions 101

Explanation

Pro

^start of line

Group 1(0|[1-9]\d*)

1st Alternative0

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2nd Alternative[1-9]\d*

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

\d*a digit, repeated any number of times

Group 2(\.)?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 3(\d*)?

?repeats the group contents below at most once:

\d*a digit, repeated any number of times

$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|[1-9]\d*)(\.)?(\d*)?$

New

121123/\3465346ss
5/\3465346
3/\\\01777
3\017773\
225555.25544444
22.22
222.22
222.5555555

121123/\3465346ss
5/\3465346
3/\\\01777
3\017773\
225555.25544444
22.22
222.22
222.5555555