Split a quoted string with a delimiter

Question

I want to split a string with a delimiter white space. but it should handle quoted strings intelligently. E.g. for a string like

\"John Smith\" Ted Barry 
<         


        

Answer 1

This is my own version, clean up from http://pastebin.com/aZngu65y (posted in the comment). It can take care of Unicode. It will clean up all excessive spaces (even in quote) - this can be good or bad depending on the need. No support for escaped quote.

private static String[] parse(String param) {
  String[] output;

  param = param.replaceAll("\"", " \" ").trim();
  String[] fragments = param.split("\\s+");

  int curr = 0;
  boolean matched = fragments[curr].matches("[^\"]*");
  if (matched) curr++;

  for (int i = 1; i < fragments.length; i++) {
    if (!matched)
      fragments[curr] = fragments[curr] + " " + fragments[i];

    if (!fragments[curr].matches("(\"[^\"]*\"|[^\"]*)"))
      matched = false;
    else {
      matched = true;

      if (fragments[curr].matches("\"[^\"]*\""))
        fragments[curr] = fragments[curr].substring(1, fragments[curr].length() - 1).trim();

      if (fragments[curr].length() != 0)
        curr++;

      if (i + 1 < fragments.length)
        fragments[curr] = fragments[i + 1];
    }
  }

  if (matched) { 
    return Arrays.copyOf(fragments, curr);
  }

  return null; // Parameter failure (double-quotes do not match up properly).
}

Sample input for comparison:

"sdfskjf" sdfjkhsd "hfrif ehref" "fksdfj sdkfj fkdsjf" sdf sfssd


asjdhj    sdf ffhj "fdsf   fsdjh"
日本語　中文 "Tiếng Việt" "English"
    dsfsd    
   sdf     " s dfs    fsd f   "  sd f   fs df  fdssf  "日本語　中文"
""   ""     ""
"   sdfsfds "   "f fsdf

(2nd line is empty, 3rd line is spaces, last line is malformed). Please judge with your own expected output, since it may varies, but the baseline is that, the 1st case should return [sdfskjf, sdfjkhsd, hfrif ehref, fksdfj sdkfj fkdsjf, sdf, sfssd].

Answer 2

Try this ugly bit of code.

    String str = "hello my dear \"John Smith\" where is Ted Barry";
    List<String> list = Arrays.asList(str.split("\\s"));
    List<String> resultList = new ArrayList<String>();
    StringBuilder builder = new StringBuilder();
    for(String s : list){
        if(s.startsWith("\"")) {
            builder.append(s.substring(1)).append(" ");
        } else {
            resultList.add((s.endsWith("\"") 
                    ? builder.append(s.substring(0, s.length() - 1)) 
                    : builder.append(s)).toString());
            builder.delete(0, builder.length());
        }
    }
    System.out.println(resultList);     

Answer 3

commons-lang has a StrTokenizer class to do this for you, and there is also java-csv library.

Example with StrTokenizer:

String params = "\"John Smith\" Ted Barry"
// Initialize tokenizer with input string, delimiter character, quote character
StrTokenizer tokenizer = new StrTokenizer(params, ' ', '"');
for (String token : tokenizer.getTokenArray()) {
   System.out.println(token);
}

Output:

John Smith
Ted
Barry

Answer 4

After messing around with it, you can use Regex for this. Run the equivalent of "match all" on:

((?<=("))[\w ]*(?=("(\s|$))))|((?<!")\w+(?!"))

A Java Example:

import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class Test
{ 
    public static void main(String[] args)
    {
        String someString = "\"Multiple quote test\" not in quotes \"inside quote\" \"A work in progress\"";
        Pattern p = Pattern.compile("((?<=(\"))[\\w ]*(?=(\"(\\s|$))))|((?<!\")\\w+(?!\"))");
        Matcher m = p.matcher(someString);

        while(m.find()) {
            System.out.println("'" + m.group() + "'");
        }
    }
}

Output:

'Multiple quote test'
'not'
'in'
'quotes'
'inside quote'
'A work in progress'

The regular expression breakdown with the example used above can be viewed here:

http://regex101.com/r/wM6yT9

---

With all that said, regular expressions should not be the go to solution for everything - I was just having fun. This example has a lot of edge cases such as the handling unicode characters, symbols, etc. You would be better off using a tried and true library for this sort of task. Take a look at the other answers before using this one.

Answer 5

well, i made a small snipet that does what you want and some more things. since you did not specify more conditions i did not go through the trouble. i know this is a dirty way and you can probably get better results with something that is already made. but for the fun of programming here is the example:

    String example = "hello\"John Smith\" Ted Barry lol\"Basi German\"hello";
    int wordQuoteStartIndex=0;
    int wordQuoteEndIndex=0;

    int wordSpaceStartIndex = 0;
    int wordSpaceEndIndex = 0;

    boolean foundQuote = false;
    for(int index=0;index<example.length();index++) {
        if(example.charAt(index)=='\"') {
            if(foundQuote==true) {
                wordQuoteEndIndex=index+1;
                //Print the quoted word
                System.out.println(example.substring(wordQuoteStartIndex, wordQuoteEndIndex));//here you can remove quotes by changing to (wordQuoteStartIndex+1, wordQuoteEndIndex-1)
                foundQuote=false;
                if(index+1<example.length()) {
                    wordSpaceStartIndex = index+1;
                }
            }else {
                wordSpaceEndIndex=index;
                if(wordSpaceStartIndex!=wordSpaceEndIndex) {
                    //print the word in spaces
                    System.out.println(example.substring(wordSpaceStartIndex, wordSpaceEndIndex));
                }
                wordQuoteStartIndex=index;
                foundQuote = true;
            }
        }

        if(foundQuote==false) {
            if(example.charAt(index)==' ') {
                wordSpaceEndIndex = index;
                if(wordSpaceStartIndex!=wordSpaceEndIndex) {
                    //print the word in spaces
                    System.out.println(example.substring(wordSpaceStartIndex, wordSpaceEndIndex));
                }
                wordSpaceStartIndex = index+1;
            }

            if(index==example.length()-1) {
                if(example.charAt(index)!='\"') {
                    //print the word in spaces
                    System.out.println(example.substring(wordSpaceStartIndex, example.length()));
                }
            }
        }
    }

this also checks for words that were not separated with a space after or before the quotes, such as the words "hello" before "John Smith" and after "Basi German".

when the string is modified to "John Smith" Ted Barry the output is three strings, 1) "John Smith" 2) Ted 3) Barry

The string in the example is hello"John Smith" Ted Barry lol"Basi German"hello and prints 1)hello 2)"John Smith" 3)Ted 4)Barry 5)lol 6)"Basi German" 7)hello

Hope it helps