Java function matches is not recognizing [0-9]+ for numbers

Question

I'm getting a phone number from an external API call and I'm trying to detect if it is indeed a number (I don't care at this point if it's a valid phone number). For simplicity's sake, I tried:

String number = phone.replace("+", "").replace(" ", "").trim();
if (number.matches("[0-9]+")) {
    return true;
}

The string I'm getting in number is something like ‪331234212453 but matches returns false. What is weird is that when I inspect the number variable, copy its value and try:

‪"331234212453".matches("[0-9]+")

It still does not work. Now if I type those same numbers and use matches then I get it to work. Could there be some kind of encoding messing up with the string? And if so how do I fix it?

Edit: Forgot to say that I tried number.matches("\\d+") and it also does not work.

Use `String.getBytes("UTF-8")` and examine the individual byte values to see if something unexpected is in there. — President James K. Polk, Dec 14 '13 at 14:50
@Ricardo Unicode replacement of control characters: http://stackoverflow.com/questions/6198986/how-can-i-replace-non-printable-unicode-characters-in-java — Brian, Dec 14 '13 at 14:53
@Ricardo - could you post a few examples of failing input? also - did you consider using replaceAll() instead of replace() ? — radai, Dec 14 '13 at 14:54
@radai What do you mean by example? I put one in my question, `331234212453`. — Ricardo, Dec 14 '13 at 14:58
@Ricardo - that means you have some control character in there. try printing out character by character and see what it is — radai, Dec 14 '13 at 14:59
@GregS `getBytes` returns [-30, -128, -86, 57, 51, 48, 50] for "‪9302". What does that mean? — Ricardo, Dec 14 '13 at 15:01

score 2 · Answer 1 · answered Dec 14 '13 at 14:50

2

1st of all when you want to clear all whitespaces you usually dont want to settle for just space. this is much safer:

replaceAll("\\s+","")

as it removes any number of consecutive whitespace characters, and not just spaces. next up, there's a digit class in java regexp syntax, so you could try

matches("\\d+")

also - notice the difference between replace() (which deals with chars) and replaceAll() (which deals in strings and patterns)

answered Dec 14 '13 at 14:50

radai

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Thanks. Forgot to say that I had tried with `number.matches("\\d+")` but it also doesn't work. – Ricardo Dec 14 '13 at 14:53
@OliCharlesworth - OP did not provide specific examples of failing input, so we're left guessing – radai Dec 14 '13 at 14:53
@radai What do you mean by example? I put the number I'm trying to match in my question. Here is a direct copy from one that is not working in my inspector when I try it, not sure it will matter here: `"‪9302".matches("\\d+")`. This is returning false for me there. – Ricardo Dec 14 '13 at 14:56
@radai and using `replaceAll("\\s+","")` does not help either. – Ricardo Dec 14 '13 at 15:03

Java function matches is not recognizing [0-9]+ for numbers

1 Answers1