Regular Expressions 101

^start of line

Non-Capturing Group(?:[0-4](?:\.5)?|5)

1st Alternative[0-4](?:\.5)?

Character Class[0-4]

0-4one character from 0 (48₁₀) to 4 (52₁₀)

Non-Capturing Group(?:\.5)?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

5the literal 5 (53₁₀ / 65₈ / 35₁₆)

2nd Alternative5

5the literal 5 (53₁₀ / 65₈ / 35₁₆)

$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

^(?:[0-4](?:\.5)?|5)$

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