Question

I would like some guidance on how to split a string into N number of separate strings based on a arithmetical operation; for example string.length()/300.

I am aware of ways to do it with delimiters such as

testString.split(",");

but how does one uses greedy/reluctant/possessive quantifiers with the split method?

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Update: As per request a similar example of what am looking to achieve;

String X = "32028783836295C75546F7272656E745C756E742E657865000032002E002E005C0"

Resulting in X/3 (more or less… done by hand)

X[0] = 32028783836295C75546F

X[1] = 6E745C756E742E6578650

x[2] = 65000032002E002E005C0

Dont worry about explaining how to put it into the array, I have no problem with that, only on how to split without using a delimiter, but an arithmetic operation

Answer 1

You could do that by splitting on (?<=\G.{5}) whereby the string aaaaabbbbbccccceeeeefff would be split into the following parts:

aaaaa
bbbbb
ccccc
eeeee
fff

The \G matches the (zero-width) position where the previous match occurred. Initially, \G starts at the beginning of the string. Note that by default the . meta char does not match line breaks, so if you want it to match every character, enable DOT-ALL: (?s)(?<=\G.{5}).

A demo:

class Main {
  public static void main(String[] args) {
    int N = 5;
    String text = "aaaaabbbbbccccceeeeefff";
    String[] tokens = text.split("(?<=\\G.{" + N + "})");
    for(String t : tokens) {
      System.out.println(t);
    }
  }
}

which can be tested online here: http://ideone.com/q6dVB

EDIT

Since you asked for documentation on regex, here are the specific tutorials for the topics the suggested regex contains:

• \G, see: http://www.regular-expressions.info/continue.html
• (?<=...), see: http://www.regular-expressions.info/lookaround.html
• {...}, see: http://www.regular-expressions.info/repeat.html