Replace Last Occurrence of a character in a string

Question

I am having a string like this

"Position, fix, dial"

I want to replace the last double quote(") with escape double quote(\")

The result of the string is to be

"Position, fix, dial\"

How can I do this. I am aware of replacing the first occurrence of the string. but don't know how to replace the last occurrence of a string

Bernhard Barker · Answer 1 · 2013-05-21T08:47:32.570

61

This should work:

String replaceLast(String string, String substring, String replacement)
{
  int index = string.lastIndexOf(substring);
  if (index == -1)
    return string;
  return string.substring(0, index) + replacement
          + string.substring(index+substring.length());
}

This:

System.out.println(replaceLast("\"Position, fix, dial\"", "\"", "\\\""));

Prints:

"Position, fix, dial\"

Test.

edited May 21 '13 at 08:47

answered May 21 '13 at 08:37

Bernhard Barker

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This is better than the accepted answer because it is general purpose. – demongolem Jul 22 '14 at 03:43

yavuzkavus · Accepted Answer · 2019-06-06T09:50:43.813

44

String str = "\"Position, fix, dial\"";
int ind = str.lastIndexOf("\"");
if( ind>=0 )
    str = new StringBuilder(str).replace(ind, ind+1,"\\\"").toString();
System.out.println(str);

Update

 if( ind>=0 )
    str = new StringBuilder(str.length()+1)
                .append(str, 0, ind)
                .append('\\')
                .append(str, ind, str.length())
                .toString();

edited Jun 06 '19 at 09:50

answered May 21 '13 at 08:36

yavuzkavus

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11
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Just asking. Why not like this? `String str = "\"Position, fix, dial\""; str.replaceAll("[\"]\\Z", "\""); System.out.println(str);` – Dudeist Nov 05 '14 at 23:47
yes, you can use something like **str = str.replaceAll("[\"]\\Z", "\\\\\"")**. But it will replace the last quot at the end of input. it wont work for < **"Position, fix, dial" again** >. – yavuzkavus Nov 06 '14 at 13:44
2

@Dudeist because that's much less readable. – Patrick Jul 20 '15 at 04:25

score 3 · Answer 3 · answered Jul 31 '15 at 15:54

3

If you only want to remove the las character (in case there is one) this is a one line method. I use this for directories.

localDir = (dir.endsWith("/")) ? dir.substring(0,dir.lastIndexOf("/")) : dir;

answered Jul 31 '15 at 15:54

juliangonzalez

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score 2 · Answer 4 · edited May 06 '16 at 07:35

2

String docId = "918e07,454f_id,did";
StringBuffer buffer = new StringBuffer(docId);
docId = buffer.reverse().toString().replaceFirst(",",";");
docId = new StringBuffer(docId).reverse().toString();

edited May 06 '16 at 07:35

Barry Michael Doyle

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answered May 06 '16 at 07:10

user2578871

820
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1

This only works for single character things. – Kris Selbekk Jun 01 '16 at 08:51

Replace Last Occurrence of a character in a string

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