如何从字符串中删除所有非字母数字字符（Java中的小数点除外）

Question

Having this String with decimal point, I would like to remove all non alphaNumeric expect the decimal point.

 String toPharse = "the. book - cost 7.55 dollars.";

 String newPharse =  toPharse.replaceAll("[^A-Za-zd.0-9 ]", " ").replaceAll("\\s+", " ");

Currently I get "the. book cost 7.55 dollars." ;

However I would like to return "the book cost 7.55 dollars" ;

Answer 1

You can use:

String toPharse = "the. book - cost 7.55 dollars.";
toPhrase = toPharse
   .replaceAll("(?<!\\d)\\.(?!\\d)|[^a-zA-Z\\d. ]+", "")
   .replaceAll("\\h{2,}", " ");

//=> "the book cost 7.55 dollars"

RegEx Demo

RegEx Details:

• (?<!\\d) : Previous character is not a digit
• \\. : Match a dot
• (?!\\d) : Next character is not a digit
• | : OR
• [^a-zA-Z\\d. ]+ [^a-zA-Z\\d. ]+ : Match 1+ of non-alphanumeric characters that are not space or dot
• .replaceAll("\\h{2,}", " ") : is for replacing 2+ whitespaces with a single space