CODEWITHSUNDEEP
regexmatchmaxlength
Salamafet
Salamafet

Reputation: 5

Length of entire regex pattern

I try to detect if a value is an int or float with a max length of 10 characters.

My best solution is (^[0-9]{0,10}$|^([0-9]+\.[0-9]+){1,10}$) but the max length of 10 characters doesn't work with a float number.

In this other solution {^[0-9]{0,10}$|^[0-9\.]{0,10}$ max length works but the regex appear valid if the value start or end by "."

How I can control the length of entire pattern ?

Upvotes: 0

Views: 940

Answers (2)

JGNI
JGNI

Reputation: 4013

If your regex engine has positive lookaheads you can do

(?=^.{1,10}$)(^[0-9]+(\.[0-9]+)?$)

Upvotes: 1

Tim Biegeleisen
Tim Biegeleisen

Reputation: 520938

I would use an alternation here to cover both integers (no decimal point) and floats (has a decimal point):

^(?:\d{1,10}|(?![\d.]{11,})\d+\.\d+)$

Demo

Here is a breakdown of the above regex:

^                   from the start of the input
    (?:\d{1,10}     match 1 to 10 digits, no decimal point
    |               OR
    (?![\d.]{11,})  assert that we DON'T see more than 10 digits/decimal point
    \d+\.\d+)       then match a floating point number (implicitly 10 chars max)
$                   end of the input

Upvotes: 1

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