Question

I have a string:

String x = "10";

Now I want to add . between the numbers and print it like this

1.0

How can I achieve this?

Answer 1

You can split the string into the first character and the rest of the string, and then insert a dot '.' in between, like this:

String res = x.substring(0,1)+"."+x.substring(1);
//           ^^^^^^^^^^^^^^^^     ^^^^^^^^^^^^^^
//            the first digit     the rest of the string

You can also use replaceAll to do it on longer strings, like this:

String orig = "19,28,37,46";
System.out.println(orig.replaceAll("(\\d)(\\d)", "$1.$2"));

This prints

1.9,2.8,3.7,4.6