Regular Expressions 101

Explanation

Pro

1st Alternative^\.0*[1-9]\d*$

^start of line

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

0*the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated any number of times

Character Class[1-9]

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

\d*a digit, repeated any number of times

$end of line

2nd Alternative^0(\.0*[1-9]\d*)$

^start of line

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

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

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

0*the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated any number of times

Character Class[1-9]

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

\d*a digit, repeated any number of times

$end of line

3rd Alternative^[1-9]\d*?(\.\d+)?$

^start of line

Character Class[1-9]

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

\d*?a digit, repeated any number of times

Group 2(\.\d+)?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d+a digit, repeated at least once

$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

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

26 tokens

Regular Expression

^\.0*[1-9]\d*$|^0(\.0*[1-9]\d*)$|^[1-9]\d*?(\.\d+)?$

New

0
-0
0.0
0000
.0
.0000
000.
0.0
0.000000
0000.0
0000.1
========================
.1
.0001
.010
0.0001
0.1111
0.1100
0.1
1.0
101
101.0
101.000
101.0001
101.0001000
1111.00000
1000
========================
0111
010.1
0110
000001
000100

Extraction

0
-0
0.0
0000
.0
.0000
000.
0.0
0.000000
0000.0
0000.1
========================
.1
.0001
.010
0.0001
0.1111
0.1100
0.1
1.0
101
101.0
101.000
101.0001
101.0001000
1111.00000
1000
========================
0111
010.1
0110
000001
000100