Regular Expressions 101

Pro

^start of line

Positive Lookahead(?=(?:-?[\.0-9]{3,8}$)|(?:-?[0-9]{1,7}$))

1st Alternative(?:-?[\.0-9]{3,8}$)

Non-Capturing Group(?:-?[\.0-9]{3,8}$)

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

Character Class[\.0-9]{3,8}

{3,8}matches between 3 and 8 characters from the set below:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

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

$end of line

2nd Alternative(?:-?[0-9]{1,7}$)

Non-Capturing Group(?:-?[0-9]{1,7}$)

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

Character Class[0-9]{1,7}

{1,7}matches between 1 and 7 characters from the set below:

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

$end of line

Group 1(-?[0-9]+)

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

Character Class[0-9]+

+matches at least one character from the set below:

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

Non-Capturing Group(?:\.([0-9]+))?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 2([0-9]+)

Character Class[0-9]+

+matches at least one character from the set below:

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.

25 tokens

^(?=(?:-?[\.0-9]{3,8}$)|(?:-?[0-9]{1,7}$))(-?[0-9]+)(?:\.([0-9]+))?$

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