Fail in Double.parse

Question

I have a error when I tried do:

private Double isEmpty(String some) {

    LOGGER.info("Se ha llamado a isEmpty, valor: " + some);
    Double empty = null;

    try {
        if (some != null) {
            // Reemplazar porque nosotros usamos los . para los miles
            if(some.contains(".")) {
                some = some.replaceAll(".", "");
            }
            if(some.contains(",")) {
                some = some.replaceAll(",", ".");
            }
            empty = Double.parseDouble(some);
            LOGGER.info("Nuevo valor en isEmpty en Double: " + some);
        }
    } catch (Exception ex) {
        LOGGER.error("*******************");
        LOGGER.error("************ Falló la ejecución isEmpty *************");
        LOGGER.error(ex.getMessage() + ex);
        LOGGER.error(ex.getLocalizedMessage());
        LOGGER.error("*******************");
    }

    return empty;
}

In my country "1.000" this is one thousand, In America is One... Then I replace all the characters for format in English...

For example in my country : "2.035,75€" --> Two thousands thirty five with seventy five ... I can't parse this. I do replace ->

"2035.75" for that Java admit this number. BUT I get error ->

 Se ha llamado a isEmpty, valor: 19.425
2018-10-16 ERROR 6197 --- [nio-8090-exec-5] Imp  : *******************
2018-10-16 ERROR 6197 --- [nio-8090-exec-5] Imp  : ************ Falló la ejecución isEmpty *************
2018-10-16 ERROR 6197 --- [nio-8090-exec-5] Imp  : empty Stringjava.lang.NumberFormatException: empty String
2018-10-16  ERROR 6197 --- [nio-8090-exec-5] Imp  : empty String
2018-10-16  ERROR 6197 --- [nio-8090-exec-5] Imp  : *******************

luk2302 · Accepted Answer · 2018-10-16T08:49:18.783

3

replaceAll takes a regex and . is the regex char that matches anything, so some.replaceAll(".", "") replaces everything with nothing. You would need to esapce .:

some = some.replaceAll("\\.", "");

or simply use replace insteadf, which does not take in a regex but a regular CharSequence or char:

some = some.replace(".", "");

Note that if you use an IDE you might get a highlight on the regex part, I would recommnd using one:

edited Oct 16 '18 at 08:49

answered Oct 16 '18 at 08:40

luk2302

55,258
23
97
137

1

... or just use [`replace`](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#replace-java.lang.CharSequence-java.lang.CharSequence-) – khelwood Oct 16 '18 at 08:42
@khelwood but there may be more than one match to be replaced. – luk2302 Oct 16 '18 at 08:43
3

Yes, that's what replace does. "Replaces each substring of this string that matches the literal target sequence with the specified literal replacement sequence." It just doesn't use a regular expression, so you don't have to escape anything. – khelwood Oct 16 '18 at 08:44
@khelwood you are correct, I just programmed in js and got confused, there the replace with a normal string only replaces once... – luk2302 Oct 16 '18 at 08:48
@khelwood if you have more than one decimal separator in your string, you should fail anyway - what is the expected value of "123.45.67"? – spi Oct 16 '18 at 08:48
@spi In the OP's question, `.` is a thousands separator. – khelwood Oct 16 '18 at 08:48
hi All, but the problem doesn't "." is when I use Double.parseDouble "19.425" ... – EduBw Oct 16 '18 at 08:52
@EduBw please read my first sentence very carefully, I write "replaces everything with nothing" for a reason, what does "19.425" after everything is replaced with nothing? – luk2302 Oct 16 '18 at 08:54

Antimon · Answer 2 · 2018-10-16T10:06:54.030

You should consider using localization for your problem. Please see Converting different countrys currency to double using java

You could try the following:

public BigDecimal parseMoney(String some) {
    try {
        Locale yourLocale = new Locale("es", "ES");
        return parse(some, yourLocale);
    } catch (ParseException pe) {
        return null;
    }
}

public BigDecimal parse(String amount, Locale locale) throws ParseException {
    final NumberFormat format = NumberFormat.getNumberInstance(locale);
    if (format instanceof DecimalFormat) {
        ((DecimalFormat) format).setParseBigDecimal(true);
    }
    return (BigDecimal) format.parse(amount);
}

Please note that

your method isEmpty does not do what its name suggests so I changed it to parseMoney
when dealing with money you should not rely on Double so I changed the return type to BigDecimal
I assumed you are located in a Spanish speaking country so I chose the Locale("es", "ES") but make sure to adjust it as needed

Apart from the programming error this is the correct answer. But please include more content in this answer, right now it is more like a comment since basically link-only. How would OP have to change his code to do what you suggest? — luk2302, Oct 16 '18 at 08:50

score 1 · Answer 3 · answered Oct 16 '18 at 08:43

1

Change this line

some = some.replaceAll(".", "");

to

some = s.replaceAll("\\.", "");

Because . (dot) means matching with all.

answered Oct 16 '18 at 08:43

drowny

2,067
11
19

score 1 · Answer 4 · answered Oct 16 '18 at 08:45

replaceAll needs two parameter: 1st is regex and 2nd is substring which is to be replaced.

so in regex . has meaning of any single character, so your each and every character is replaced with null value as you code: some = some.replaceAll(".", "")

try this: some = some.replaceAll("\\.", "")

score -1 · Answer 5 · answered Oct 16 '18 at 08:46

-1

I think you don't need to do replaceAll. Below code should work

        String some = "19.27";
        double d = Double.parseDouble(some);
        System.out.println("String " + some + " is parse to double value : " + d);

answered Oct 16 '18 at 08:46

Deepak Jain

347
1
6

Fail in Double.parse

5 Answers5