How do you replace all of the characters in a string that do not fit a criteria. I'm having trouble specifically with the NOT operator.
Specifically, I'm trying to remove all characters that are not a digit, I've tried this so far:
String number = "703-463-9281";
String number2 = number.replaceAll("[0-9]!", ""); // produces: "703-463-9281" (no change)
String number3 = number.replaceAll("[0-9]", ""); // produces: "--"
String number4 = number.replaceAll("![0-9]", ""); // produces: "703-463-9281" (no change)
String number6 = number.replaceAll("^[0-9]", ""); // produces: "03-463-9281"
To explain: The ^ at the start of a character class will negate that class But it has to be inside the class for that to work. The same character outside a character class is the anchor for start of string/line instead.
You can try this instead:
"[^0-9]"