Question

How can I convert String s="3.78 hi bye" to double c=3.78?

Same question for String s="hi 3.78 hi bye" (take only 3.78 while ignoring the text before)

Answer 1

You can use a regex to get rid of all characters that are not a digit or a .:

String s = "hi 3.78 hi bye";
String numberOnly = s.replaceAll("[^0-9\\.]+", "");
double d = Double.parseDouble(numberOnly); //d == 3.78d

You should add some exception handling in case the original string is not properly formatted.