String split function in Java

Question

I have a String and I want to split it by ","

If suppose I have a String like,

 String test = "aa,bb,cc";

now I can split it by,

String[] spl = test.split(",");

And the spl.length is 3

If suppose my String is

 String test = ",,,";

Here the splitted String length is 0. But my expected answer is 3. My test String is dynamaic value and it may varies like, Now think I have a String like

String test = ",aa,dd,,,,,ff,gg"

Now the splited array length is 4. But I expected answer is 9 And I need to split by "," and I need the aa position at spl[1] and dd position as spl[2] and ff position as spl[7]

Can someone give the suggestion about to solve this issue..

Have a look at this post: http://stackoverflow.com/a/14602089/3579095 — Lars, Jul 28 '14 at 07:25
@Lars - gives 4 and not 3. `String[] spl = test.split("\\,", -1);` — james, Jul 28 '14 at 07:40
@No_Rulz Then please let us know on what basis did you determine that the second split should give 4 and the third split 9. — AllTooSir, Jul 28 '14 at 07:43

TheLostMind · Accepted Answer · 2014-07-28T08:14:56.057

7

Use split() with -1 as limit

     public static void main(String[] args) {
    String test = ",,,";
    System.out.println(Arrays.toString(test.split(",", -1))); // adds leading and trailing empty Strings .
    // so effectively its like adding "" before , after and between each ","

    String test1 = "aa,bb,cc";
    System.out.println(Arrays.toString(test1.split(",",-1)));
}

O/P :

[, , , ] -- > Length =4
[aa, bb, cc]

edited Jul 28 '14 at 08:14

answered Jul 28 '14 at 07:25

TheLostMind

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`,,,` gives me 4 and not 3. – james Jul 28 '14 at 07:29
1

public static void main(String[] args) { String test = ",,,"; String[] spl = test.split(",", -1); System.out.println(spl.length); } – james Jul 28 '14 at 07:30
@TheLostMind the answer is 4 not 3 – No_Rulz Jul 28 '14 at 07:31
1

@No_Rulz When you perform a split operation on a subject containing the delimiter 3 times, the output will be 4 elements, not 3 elements. Your expected result for `",,,".split(",", -1);` should be 4. Look at your example for: `"aa,bb,cc"`, the delimiter only occurs twice and you expect 3 elements to be returned, why would you not expect 4 elements to return when you have the delimiter 3 times? – Dan Temple Jul 28 '14 at 07:38
@DanTemple yes I agree with you :) – No_Rulz Jul 28 '14 at 07:53
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@all -My bad.. This does return 4(forgot that a trailing empty string will also be added when we split.).. - edited my answer. – TheLostMind Jul 28 '14 at 08:15
@TheLostMind after reading dantemple comment only I also recognize my mistake.. and thanks for your answer :) – No_Rulz Jul 28 '14 at 08:27
2

@TheLostMind Ok, but your answer is still right :) As Dan Temple said, when you have a string like `a,b,c` you have two commas, but after splitting the resulting array will hold three values. So, the OP should expect that `,,,` will be splitted to four values, not three, that would be wrong. – BackSlash Jul 28 '14 at 09:50

score 2 · Answer 2 · answered Jul 28 '14 at 07:25

2

To get the behavior you want you can just replace "," by " ,":

String test = ",,";
test = test.replace(",", " ,");
System.out.println((test.split(",").length));

answered Jul 28 '14 at 07:25

Pablo Francisco Pérez Hidalgo

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Is this extra step of modifying a string really needed ? – james Jul 28 '14 at 07:29
Misread the answer, sorry. Anyway, TheLostMind's answer is the correct one. No need to replace, the `split` method just does the job – BackSlash Jul 28 '14 at 07:30
@PabloFranciscoPérezHidalgo - it needs to be changed. See the comments there. – james Jul 28 '14 at 07:32
@james I did not see the comments, yes. It is true. If I were coding the OP program I would use replace as I answered. – Pablo Francisco Pérez Hidalgo Jul 28 '14 at 07:34
@james Do u have any suggestion about my question? – No_Rulz Jul 28 '14 at 07:35
@No_Rulz - sorry, can't think of a solution. – james Jul 28 '14 at 07:37
@No_Rulz Isn't ok for you the replace solution? – Pablo Francisco Pérez Hidalgo Jul 28 '14 at 07:38
@PabloFranciscoPérezHidalgo yes dude, it must solve my issue.. If suppose I have 50 "," means I need to use replace() and other hand side I need to use trim() function also.. It has some extra steps.. Now I used like your answer. But I look better answer dude.. – No_Rulz Jul 28 '14 at 07:41

score 0 · Answer 3 · answered Jul 28 '14 at 07:27

With the split() function, java separates a String by the Substring of your choice. If there is nothing between them, the field will not be null, it will just be skipped.

In other programming languages, you could come across something like this:

String example = ',,,'
String[] example2 = example.split(',')
print(example2.length())

This could also deliver 4. Because there are 4 spaces around the ',' chars:

1,2,3,4

String split function in Java

3 Answers3