Regular Expressions 101

^start of line

Character Class[+-]?

?matches at most one character from the set below:

+the literal + (43₁₀ / 53₈ / 2B₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 1((\\d+(\\.\\d*)?)|(\\.\\d+))

1st Alternative(\\d+(\\.\\d*)?)

Group 2(\\d+(\\.\\d*)?)

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

d+the literal d (100₁₀ / 144₈ / 64₁₆) (case insensitive), repeated at least once

Group 3(\\.\\d*)?

?repeats the group contents below at most once:

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

.any character (except for line terminators)

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

d*the literal d (100₁₀ / 144₈ / 64₁₆) (case insensitive), repeated any number of times

2nd Alternative(\\.\\d+)

Group 4(\\.\\d+)

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

.any character (except for line terminators)

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

d+the literal d (100₁₀ / 144₈ / 64₁₆) (case insensitive), repeated at least once

$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

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

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Search reference

Regular Expression

^[+-]?((\\d+(\\.\\d*)?)|(\\.\\d+))$

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