Java : split a string that containing special characters

Question

I have a string like ||81|||01|| and I want to split the string with | symbol.

I had done this way,

String str = "||81|||01||";
System.out.println(str .split("\\|").length); //printing 6 . But I am expecting 8

what is wrong with this code? | How can I split this string with that character so that I will get expected length (8)?;

@NoobUnChained if there are `n` delimiters, the string should be split into `n+1` parts. In the given input there are `7` pipes, so there should be `8` results. — Martin Ender, Apr 30 '13 at 10:30
Introduce a space at beginning and end : `" ||81|||01|| "` to get the expected result ;) — AllTooSir, Apr 30 '13 at 10:31
@NoobUnChained that's an odd hack, seeing that Java provides you the option to change the behavior using an additional argument for `split`, don't you think? — Martin Ender, Apr 30 '13 at 10:32
@NoobUnChained: No. You'll get a different result (space instead of an empty string). — Tim Pietzcker, Apr 30 '13 at 10:32

score 11 · Answer 1 · answered Apr 30 '13 at 10:29

11

Using split("\\|") is the same as split("\\|", 0), where the limit parameter 0 tells the function "omit trailing empty strings". So you are missing the last two empty strings. Use the two-argument version and supply a negative number to obtain all parts (even trailing empty ones):

str.split("\\|", -1)

answered Apr 30 '13 at 10:29

Martin Ender

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Dear downvoter, would you care to leave a comment so I can improve the answer? – Martin Ender Apr 30 '13 at 10:33

Maroun · Accepted Answer · 2013-04-30T10:33:26.843

Print:

System.out.println(Arrays.toString(str.split("\\|")));

And you'll understand why it's printing 6.

You can try doing what you want using public String[] split(String regex, int limit):

The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array.

So you should do:

System.out.println(str.split("\\|", -1).length);

Now, printing the array will print:

[, , 81, , , 01, , ] as you expected.

score 3 · Answer 3 · answered May 04 '15 at 08:59

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You can also use string.split(Pattern.quote("|"),-1) for spliting a string on a special character.

answered May 04 '15 at 08:59

Santosh

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Could you please elaborate more your answer adding a little more description about the solution you provide? – abarisone May 04 '15 at 09:17
example to split "||81|||01||" based on the special character '|' then you can use `String s="||81|||01||"; String array[]=s.split(Pattern.quote("|"),-1) ` length of the array thus obtained will be 8. – Santosh May 05 '15 at 05:32

score 1 · Answer 4 · answered Apr 30 '13 at 10:29

You need to use:

str.split("\\|", -1)

The second parameter is limit. From the javadoc:

The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array. If the limit n is greater than zero then the pattern will be applied at most n - 1 times, the array's length will be no greater than n, and the array's last entry will contain all input beyond the last matched delimiter. If n is non-positive then the pattern will be applied as many times as possible and the array can have any length. If n is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.

score 1 · Answer 5 · edited May 23 '17 at 11:59

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str.split("\\|", -1) will do the necessary. Possible duplicate : Here

edited May 23 '17 at 11:59

Community

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answered Apr 30 '13 at 10:30

javadev

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score 1 · Answer 6 · answered Apr 30 '13 at 10:36

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String str = "||81|||01||"; System.out.println(str.split("\\|", 8).length);

The second argument to split specifies maximum number of matches. Single argument split is like invoking split(str, 0) which leaves out trailing strings. See javadoc of both for more explaination.

answered Apr 30 '13 at 10:36

Datta

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using `8` is quite inflexible. if you just use a negative argument (like the other answers), you'll simply get all parts, no matter how many `|` there are in `str` – Martin Ender Apr 30 '13 at 10:38

Java : split a string that containing special characters

6 Answers6