CODEWITHSUNDEEP
javaregexsplit
Raja D
Raja D

Reputation:

How can split a string which contains only delimiter?

I am using the following code:

String sample = "::";
String[] splitTime = sample.split(":");
// extra detail omitted
System.out.println("Value 1 :"+splitTime[0]);
System.out.println("Value 2 :"+splitTime[1]);
System.out.println("Value 3 :"+splitTime[2]);

I am getting ArrayIndexOutofBound exception. How does String.split() handle consecutive or trailing / opening delimiters?

See also:

Upvotes: 17

Views: 13108

Answers (5)

Michael Myers
Michael Myers

Reputation: 192035

Alnitak is correct that trailing empty strings will be discarded by default.

If you want to have trailing empty strings, you should use split(String, int) and pass a negative number as the limit parameter.

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.

Note that split(aString) is a synonym for split(aString, 0):

This method works as if by invoking the two-argument split method with the given expression and a limit argument of zero. Trailing empty strings are therefore not included in the resulting array.

Also, you should use a loop to get the values from the array; this avoids a possible ArrayIndexOutOfBoundsException.

So your corrected code should be (assuming you want the trailing empty strings):

String sample = "::";
String[] splitTime = sample.split(":", -1);
for (int i = 0; i < splitTime.length; i++) {
    System.out.println("Value " + i + " : \"" + splitTime[i] + "\"");
}

Output:

Value 0 : ""
Value 1 : ""
Value 2 : ""

Upvotes: 27

Alnitak
Alnitak

Reputation: 340045

From the J2SE API manual:

Trailing empty strings are therefore not included in the resulting array.

So, if you pass in "::" you'll get an empty array because all of the delimiters are trailing.

If you want to make sure that you get no more than three entries you should use:

String[] splitTime = sample.split(":", 3);

With an input of "::" that would indeed give you three empty strings in the output array.

However if the input only happens to have one ":" in it then you'll still only get two elements in your array.

Upvotes: 4

Matthew Sposato
Matthew Sposato

Reputation: 1635

Like this perhaps?

int ndx = 0;
StringTokenizer t = new StringTokenizer(": : ::::",":");
while (t.hasMoreElements())
{
    System.out.println(String.format("Value %d : %s", ++ndx,t.nextElement()));
}

Upvotes: 1

Jugal
Jugal

Reputation: 201

Use the function StringTokenizer in which u pass the string and the second argument as delimiter

use splittime.length function to find the length

Upvotes: 0

user53378
user53378

Reputation: 160

you should check the length of the splitTime array.

Upvotes: 0

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