Regular Expressions 101

Pro

Positive Lookbehind(?<=^|\s)

1st Alternative^

^start of line

2nd Alternative\s

\sany whitespace character

Non-Capturing Group(?:0|-?[1-9]\d*|-?[1-9]\d{0,2}(?:,\d{3})+)

1st Alternative0

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2nd Alternative-?[1-9]\d*

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

Character Class[1-9]

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

\d*a digit, repeated any number of times

3rd Alternative-?[1-9]\d{0,2}(?:,\d{3})+

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

Character Class[1-9]

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

\d{0,2}a digit, repeated between 0 and 2 times

Non-Capturing Group(?:,\d{3})+

+repeats the group contents below at least once:

,the literal , (44₁₀ / 54₈ / 2C₁₆)

\d{3}a digit, repeated exactly 3 times

Positive Lookahead(?=\s|$)

1st Alternative\s

\sany whitespace character

2nd Alternative$

$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.

26 tokens

(?<=^|\s)(?:0|-?[1-9]\d*|-?[1-9]\d{0,2}(?:,\d{3})+)(?=\s|$)

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