CODEWITHSUNDEEP
javaregexstring
BUKTOP
BUKTOP

Reputation: 971

Java split using regex lookahead - character not followed by character

I need to split the string to the substings in order to sort them to quoted and not quoted ones. The single quote character is used as a separator, and two single quotes represents an escape sequence and means that they shall not be used for splitting.

For example:

"111 '222''22' 3333"

shall be splitted as

"111", "222''22", "3333"

no matter with or without whitespaces.

So, I wrote the following code, but it does not work. Tried lookbehind with "\\'(?<!\\')" as well, but with no success. Please help 

    String rgxSplit="\\'(?!\\')";
    String text="";
    Scanner s=new Scanner(System.in);

    System.out.println("\""+rgxSplit+"\"");
    text=s.nextLine();
    while(!text.equals(""))
    {
        String [] splitted=text.split(rgxSplit);
        for(int i=0;i<splitted.length;i++)
        {
            if(i%2==0)
            {
                System.out.println("+" + splitted[i]);
            }
            else
            {
                System.out.println("-" + splitted[i]);
            }
        }
        text=s.nextLine();
    }

Output:

$ java ParseTest
"\'(?!\')"
111 '222''22' 3333
+111
-222'
+22
- 3333

Upvotes: 1

Views: 1190

Answers (2)

Maria Ivanova
Maria Ivanova

Reputation: 1146

This should split on a single quote (when it is not doubled), and in the case of three consecutive, it will group the first two and will split on the third.

String [] splitted=text.split("(?<!') *' *(?!')|(?<='') *' *");

Upvotes: 2

Bohemian
Bohemian

Reputation: 424983

To split on single apostrophes use look arounds both sides of the apostrophe:

String[] parts = str.split(" *(?<!')'(?!') *");

See live demo on ideone.

Upvotes: 0

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