CODEWITHSUNDEEP
javastringstringtokenizersplit
user69514
user69514

Reputation: 27629

Java StringTokenizer, empty null tokens

I am trying to split a string into 29 tokens..... stringtokenizer won't return null tokens. I tried string.split, but I believe I am doing something wrong:

String [] strings = line.split(",", 29);

sample inputs:

10150,15:58,23:58,16:00,00:00,15:55,23:55,15:58,00:01,16:03,23:58,,,,,16:00,23:22,15:54,00:03,15:59,23:56,16:05,23:59,15:55,00:01,,,,
10155,,,,,,,,,,,07:30,13:27,07:25,13:45,,,,,,,,,,,07:13,14:37,08:01,15:23
10160,10:00,16:02,09:55,16:03,10:06,15:58,09:48,16:07,09:55,16:00,,,,,09:49,15:38,10:02,16:04,10:00,16:00,09:58,16:01,09:57,15:58,,,,

Upvotes: 10

Views: 20138

Answers (5)

user2675617
user2675617

Reputation: 250

use this org.springframework.util.StringUtils

org.springframework.util.StringUtils.delimitedListToStringArray(data, delimit);

This class delivers some simple functionality provides easy-to-use methods to convert between delimited strings, such as CSV strings, and collections and arrays.

Upvotes: 1

polygenelubricants
polygenelubricants

Reputation: 383746

If you want the trailing empty strings to be kept, but you don't want to give a magic number for maximum, use a negative limit:

line.split(",", -1)

If line.equals("a,,c"), then line.split(",", -1)[1].isEmpty(); it's not null. This is because when "," is the delimiter, then ",," has an empty string between the two delimiters, not null.

Example:

Using the explanation above, consider the following example: ",,"

Although you might expect ",", null, and ",".

The actual result is ",", "" and ","

If you want null instead of empty strings in the array returned by split, then you'd have to manually scan the array and replace them with null. I'm not sure why s == null is better than s.isEmpty(), though.

See also

Upvotes: 16

Thomas Auinger
Thomas Auinger

Reputation: 2095

Use StringUtils.splitPreserveAllTokens() in Apache Commons Lang library

Upvotes: 5

Wasim
Wasim

Reputation: 21

If you want empty tokens to be retained string.split() won't work satisfactorily. StringTokenizer will also not work. I have come with following method, which might be helpful for you:

public static String[] splitTotokens(String line, String delim){
    String s = line;
    int i = 0;

    while (s.contains(delim)) {
        s = s.substring(s.indexOf(delim) + delim.length());
        i++;
    }
    String token = null;
    String remainder = null;
    String[] tokens = new String[i];

    for (int j = 0; j < i; j++) {
        token = line.substring(0, line.indexOf(delim));
        // System.out.print("#" + token + "#");
        tokens[j] = token;
        remainder = line.substring(line.indexOf(delim) + delim.length());
        //System.out.println("#" + remainder + "#");

        line = remainder;
    }
    return tokens;
}

Upvotes: 0

Wasim
Wasim

Reputation: 21

If you want empty tokens to be retained string.split won't work satisfactorily. StringTokenizer will also no work. I have come with following method, which might be helpful for you

public static String[] splitTotokens(String line, String delim){
  String s = line;
  int i = 0;

  while (s.contains(delim)) {
  s = s.substring(s.indexOf(delim) + delim.length());
      i++;
  }
  String token = null;
  String remainder = null;
  String[] tokens = new String[i];

  for (int j = 0; j < i; j++) {
    token = line.substring(0, line.indexOf(delim));
    //System.out.print("#" + token + "#");
    tokens[j] = token;
    remainder = line.substring(line.indexOf(delim) + delim.length());
    //System.out.println("#" + remainder + "#");
    line = remainder;
    }

  return tokens;`  
 }

Upvotes: 2

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