Trim a string based on the string length

Question

I want to trim a string if the length exceeds 10 characters.

Suppose if the string length is 12 (String s=\"abcdafghijkl\"), then the new trimmed string

Answer 1

Here is the Kotlin solution

One line,

if (yourString?.length!! >= 10) yourString?.take(90).plus("...") else yourString

Traditional,

if (yourString?.length!! >= 10) {
  yourString?.take(10).plus("...")
 } else {
  yourString
 }

Answer 2

Just in case you are looking for a way to trim and keep the LAST 10 characters of a string.

s = s.substring(Math.max(s.length(),10) - 10);

Answer 3

As usual nobody cares about UTF-16 surrogate pairs. See about them: What are the most common non-BMP Unicode characters in actual use? Even authors of org.apache.commons/commons-lang3

You can see difference between correct code and usual code in this sample:

public static void main(String[] args) {
    //string with FACE WITH TEARS OF JOY symbol
    String s = "abcdafghi\uD83D\uDE02cdefg";
    int maxWidth = 10;
    System.out.println(s);
    //do not care about UTF-16 surrogate pairs
    System.out.println(s.substring(0, Math.min(s.length(), maxWidth)));
    //correctly process UTF-16 surrogate pairs
    if(s.length()>maxWidth){
        int correctedMaxWidth = (Character.isLowSurrogate(s.charAt(maxWidth)))&&maxWidth>0 ? maxWidth-1 : maxWidth;
        System.out.println(s.substring(0, Math.min(s.length(), correctedMaxWidth)));
    }
}

Answer 4

StringUtils.abbreviate from Apache Commons Lang library could be your friend:

StringUtils.abbreviate("abcdefg", 6) = "abc..."
StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
StringUtils.abbreviate("abcdefg", 4) = "a..."

Commons Lang3 even allow to set a custom String as replacement marker. With this you can for example set a single character ellipsis.

StringUtils.abbreviate("abcdefg", "\u2026", 6) = "abcde…"

Answer 5

Or you can just use this method in case you don't have StringUtils on hand:

public static String abbreviateString(String input, int maxLength) {
    if (input.length() <= maxLength) 
        return input;
    else 
        return input.substring(0, maxLength-2) + "..";
}

Answer 6

There is a Apache Commons StringUtils function which does this.

s = StringUtils.left(s, 10)

If len characters are not available, or the String is null, the String will be returned without an exception. An empty String is returned if len is negative.

StringUtils.left(null, ) = null
StringUtils.left(, -ve) = ""
StringUtils.left("", *) = ""
StringUtils.left("abc", 0) = ""
StringUtils.left("abc", 2) = "ab"
StringUtils.left("abc", 4) = "abc"

StringUtils.Left JavaDocs

Courtesy:Steeve McCauley