How to remove the unused positional Parameters from String format

Question

I have a pattern like :

String pattern = "{0},{1},{2},{3},{4},{5},{6},{7}";

I have a Array of values to get Populated in this pattern:

Object[] values = new String[8];

This Array of values is dynamic , sometimes it gets populated with full 8 allotted slots and some times it is less than that, but never more than allotted size.

Now when it is less than 8 slots(e.g), and when i format it using

MessageFormat messageFormat = new MessageFormat(pattern);
header = new StringBuffer();
messageFormat.format(values, header, null);

theirs remains those position whose substitutes are not found:

e.g:

    String pattern = "{0},{1},{2},{3},{4}";
    Object[] values = {"abc", "cde", "gef"};
    MessageFormat messageFormat = new MessageFormat(pattern);
    StringBuffer header = new StringBuffer();
    System.out.println(messageFormat.format(values, header, null));

output

abc,cde,gef,{3},{4}

But what I want is those position should also be moved: As final output should be like this:

abc, cde, gef

Probably your actual format is more complicated. But in this particular case you might want just to join strings: http://stackoverflow.com/questions/187676/java-equivalents-of-c-sharp-string-format-and-string-join — default locale, Jan 14 '15 at 13:14
I think this will not make any difference, as still in ArrayList my values may be less than the position parameters provided in the pattern....@Andre — BigBang, Jan 14 '15 at 13:17
yes absolute my format is more complicated, as this pattern will be define globally and every one below should follow to format their string in this format — BigBang, Jan 14 '15 at 13:25
Should all the non-placeholder parts of the template remain? Or should the complete template be truncated from the last filled-in placeholder? In other words, do you really want "abc, cde, gef" or do you want "abc, cde, gef,,"? — Adriaan Koster, Jan 14 '15 at 13:26
All non place holder should be removed from the final output, Yes I want the strings as -- "abc, cde, gef" — BigBang, Jan 14 '15 at 13:29
@BigBang It's unclear which placeholders should be removed. Suppose you have a pattern like this: `{0},{1}&{2}-0_o-{3}-here-comes-fourth-{4}_message_to_user_{5}-again-{3},{2},{1}`. What should happen if there're only 3 arguments? — default locale, Jan 14 '15 at 13:38
then third, fourth and fifth(3,4, 5) should be removed and 0,1,2 should be populated — BigBang, Jan 14 '15 at 13:41
Actually the format is of csv file, so what i want is the header and the children should follow the same structure, and in the future if I need to change the sequence, then I only need to change the pattern. — BigBang, Jan 14 '15 at 13:56

score 0 · Accepted Answer · answered Jan 14 '15 at 13:27

String pattern = "{0},{1},{2},{3},{4}";
String[] patternArray = pattern.split("}");
Object[] values = {"abc", "cde", "gef"};
StringBuilder patternBuilder = new StringBuilder();
for(int i = 0; i < values.length; ++i){
  patternBuilder.append(patternArray[i]).append("}");
}
pattern = patternBuilder.toString();
MessageFormat messageFormat = new MessageFormat(pattern);
StringBuffer header = new StringBuffer();
System.out.println(messageFormat.format(values, header, null));

How to remove the unused positional Parameters from String format

1 Answers1