Regular Expressions 101

^start of line

Group 1([0-9]|[1-9][0-9]|[1-9][0-9][0-9])

1st Alternative[0-9]

Character Class[0-9]

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

2nd Alternative[1-9][0-9]

Character Class[1-9]

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

Character Class[0-9]

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

3rd Alternative[1-9][0-9][0-9]

Character Class[1-9]

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

Character Class[0-9]

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

Character Class[0-9]

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

$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

^([0-9]|[1-9][0-9]|[1-9][0-9][0-9])$

New

<--! select 0..999 sequences -->
0
9
00
09
10
99
000
001
002
004
010
011
021
100
101
110
115
120
125
127
135
139
141
201
222
230
245
247
250
254 sgnlfsf
2340
345
255
853
999