Regular Expressions 101

^start of line

Negative Lookahead(?!0[0-9])

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[0-9]

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

Character Class[0-9]+

+matches at least one character from the set below:

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

Group 1(\.(?>[0-9])[0-9]{0,5})?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Atomic Group(?>[0-9])

Character Class[0-9]

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

Character Class[0-9]{0,5}

{0,5}matches between 0 and 5 characters 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

Regular Expression

^(?!0[0-9])[0-9]+(\.(?>[0-9])[0-9]{0,5})?$

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