StringUtils isNumeric returns true when input is "???", why?

Question

I was reading the commons.apache.org isNumeric method definition and it states:

StringUtils.isNumeric("???") = true;

I am not sure why "???" is considered to be numeric. My guesses are:

A "?" is considered a unicode digit
It is some kind of regex pattern

score 10 · Accepted Answer · answered Jul 25 '16 at 21:10

10

I was able to find the answer to this question by looking at the StringUtils source code for the isNumeric method. In the source code that line appears as:

StringUtils.isNumeric("\u0967\u0968\u0969")  = true

Where u0967, u0968, u0969 are Devangari Digits one, two, and three respectively. This may be a browser issue causing the characters to not be rendered correctly in the API.

answered Jul 25 '16 at 21:10

dspano

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And for what it's worth, my browser displays presumably-correct glyphs for those digits, rather than subbing in question marks. – John Bollinger Nov 03 '16 at 15:10

score 3 · Answer 2 · answered Jul 25 '16 at 21:14

3

Looking at the code, the example is

StringUtils.isNumeric("\u0967\u0968\u0969")  = true

\u0967 is १, which is "Devanagari Digit One"

\u0967 is २, which is "Devanagari Digit Two"

So they are digits!

answered Jul 25 '16 at 21:14

Jean Logeart

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StringUtils isNumeric returns true when input is "???", why?

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