Java Regex - reduce spaces in a string

Question

I don\'t have time to get my head around regex and I need a quick answer. Platform is Java.

I need the string

\"Some text   with  spaces\"
<         


        

Answer 1

You need to use a constant of java.util.regex.Pattern for avoid recompiled the expression every time:

private static final Pattern REGEX_PATTERN = 
        Pattern.compile(" {2,}");

public static void main(String[] args) {
    String input = "Some text   with spaces";
    System.out.println(
        REGEX_PATTERN.matcher(input).replaceFirst(" ")
    );  // prints "Some text with spaces"
}

In another way, the Apache Commons Lang include in the class StringUtils the method normalizeSpace.

Answer 2

If we're talking specifically about spaces, you want to be testing specifically for spaces:

MyString = MyString.replaceAll(" +", " ");

Using \s will result in all whitespace being replaced - sometimes desired, othertimes not.

Also, a simpler way to only match 2 or more is:

MyString = MyString.replaceAll(" {2,}", " ");

(Of course, both of these examples can use \s if any whitespace is desired to be replaced with a single space.)

Answer 3

String a = "Some    text  with   spaces";
String b = a.replaceAll("\\s+", " ");
assert b.equals("Some text with spaces");

Answer 4

For Java (not javascript, not php, not anyother):

txt.replaceAll("\\p{javaSpaceChar}{2,}"," ")