How to replace comma (,) with a dot (.) using java

Question

I am having a String str = 12,12 I want to replace the ,(comma) with .(Dot) for decimal number calculation, Currently i am trying this :

 if( str.indexOf(",") != -1 )
 {
     str.replaceAll(",","\\.");
 }

please help

You know that the method doesn't modify the String but returns the modified one, right? — Jan Zyka, May 18 '11 at 11:37
possible duplicate of [java replaceAll()](http://stackoverflow.com/questions/1092416/java-replaceall) — Isaac Truett, May 18 '11 at 11:50

MByD · Answer 1 · 2011-05-18T11:47:58.177

53

Your problem is not with the match / replacement, but that String is immutable, you need to assign the result:

str = str.replaceAll(",","."); // or "\\.", it doesn't matter...

edited May 18 '11 at 11:47

answered May 18 '11 at 11:38

MByD

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exactly that is the issue. – Dev G Sep 19 '13 at 02:57

Bozho · Answer 2 · 2011-05-18T11:40:32.047

19

Just use replace instead of replaceAll (which expects regex):

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

or

str = str.replace(',', '.');

(replace takes as input either char or CharSequence, which is an interface implemented by String)

Also note that you should reassign the result

edited May 18 '11 at 11:40

answered May 18 '11 at 11:34

Bozho

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davek · Answer 3 · 2015-06-12T06:42:44.940

16

str = str.replace(',', '.')

should do the trick.

edited Jun 12 '15 at 06:42

answered May 18 '11 at 11:34

davek

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score 2 · Answer 4 · answered May 18 '11 at 11:35

2

if(str.indexOf(",")!=-1) { str = str.replaceAll(",","."); }

or even better

str = str.replace(',', '.');

answered May 18 '11 at 11:35

Jan Zyka

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1

This: `"\."` will not compile – MByD May 18 '11 at 11:37

score 2 · Answer 5 · answered May 18 '11 at 11:35

2

Just use str.replace(',', '.') - it is both fast and efficient when a single character is to be replaced. And if the comma doesn't exist, it does nothing.

answered May 18 '11 at 11:35

lonerook

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score 2 · Answer 6 · answered May 18 '11 at 11:39

2

For the current information you are giving, it will be enought with this simple regex to do the replacement:

str.replaceAll(",", ".");

answered May 18 '11 at 11:39

Jav_Rock

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score 1 · Answer 7 · edited Jun 09 '15 at 16:20

1

in the java src you can add a new tool like this:

public static String remplaceVirguleParpoint(String chaine) {
       return chaine.replaceAll(",", "\\.");
}

edited Jun 09 '15 at 16:20

josliber

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answered Jun 09 '15 at 16:16

Merlook

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score 1 · Answer 8 · answered Aug 01 '17 at 15:01

1

Use this:

String str = " 12,12"
str = str.replaceAll("(\\d+)\\,(\\d+)", "$1.$2");
System.out.println("str:"+str); //-> str:12.12

hope help you.

answered Aug 01 '17 at 15:01

Yugerten

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score 0 · Answer 9 · answered Jun 02 '21 at 11:38

If you want to change it in general because you are from Europe and want to use dots instead of commas for reading an input with a scaner you can do it like this:

Scanner sc = new Scanner(System.in);
sc.useLocale(Locale.US);
System.out.println(sc.locale().getDisplayCountry());

Double accepted with comma instead of dot

How to replace comma (,) with a dot (.) using java

9 Answers9

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