regex101: PCRE (Legacy) Match Workspace

Pro

^start of line

Positive Lookahead(?=.*[1-9])

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

Character Class[1-9]

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

Negative Lookahead(?!0\d)

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

\da digit

Group 1(\d{0,3}(?:\.\d{1,2})?)

\d{0,3}a digit, repeated between 0 and 3 times

Non-Capturing Group(?:\.\d{1,2})?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{1,2}a digit, repeated between 1 and 2 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

25 tokens

Regular Expression

^(?=.*[1-9])(?!0\d)(\d{0,3}(?:\.\d{1,2})?)$

Should match: (if decimal exists, max 3 numbers before and 2 after.)
.01
.1
0.01
0.1
1
10
10.1
10.11
105.1
999.99
88.00

Should fail:
12345678.54
00564.5412
00.451
1.
,25
..25
0025
01
00,25
0
.0
0.001
999.001
e123.12
1000

Extraction

Should match: (if decimal exists, max 3 numbers before and 2 after.)
.01
.1
0.01
0.1
1
10
10.1
10.11
105.1
999.99
88.00

Should fail:
12345678.54
00564.5412
00.451
1.
,25
..25
0025
01
00,25
0
.0
0.001
999.001
e123.12
1000