CODEWITHSUNDEEP
javaregex
user3427748
user3427748

Reputation: 61

Regex matching up to a character if it occurs

I need to match string as below:

  1. match everything upto ;
  2. If - occurs, match only upto - excluding -

For e.g. :

Pattern.compile("^(?<string>.*?);$");

Using above i can achieve half. but dont know how to change this pattern to achieve the second requirement. How do i change .*? so that it stops at forst occurance of -

I am not good with regex. Any help would be great.

EDIT

I need to capture it as group. i cant change it since there many other patterns to match and capture. Its only part of it that i have posted.

Code looks something like below. 

public static final Pattern findString = Pattern.compile("^(?<string>.*?);$");
if(findString.find())
    {
        return findString.group("string"); //cant change anything here.

    }

Upvotes: 2

Views: 1599

Answers (4)

user3427748
user3427748

Reputation: 61

I have found the solution without removing groupings.

  • (?<string>.*?) matches everything upto next grouping pattern
  • (?:-.*?)? followed by a non grouping pattern starts with - and comes zero or once.
  • ; end character.

So putting all together: 

    public static final Pattern findString = Pattern.compile("^(?<string>.*?)(?:-.*?)?;$");
    if(findString.find())
    {
       return findString.group("string"); //cant change anything here.
    }

Upvotes: 0

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626806

UPDATE

I see you have an issue in the code since you try to access .group in the Pattern object, while you need to use the .group method of the Matcher object:

public static String GetTheGroup(String str) {
    Pattern findString = Pattern.compile("(?s)^(?<string>.*?)[;-]");
    Matcher matcher = findString.matcher(str);
    if (matcher.find())
    {
        return matcher.group("string"); //you have to change something here.
    }
    else
        return "";
}

And call it as

System.out.println(GetTheGroup("abc-xyz;"));

See IDEONE demo

OLD ANSWER

Your ^(?<string>.*?);$ regex only matches 0 or more characters other than a newline from the beginning up to the first ; that is the last character in the string. I guess it is not what you expect.

You should learn more about using character classes in regex, as you can match 1 symbol from a specified character set that is defined with [...].

You can achieve this with a String.split taking the first element only and a [;-] regex that matches a ; or - literally: 

String res = "abc-xyz;".split("[;-]")[0];
System.out.println(res);

Or with replaceAll with (?s)[;-].*$ regex (that matches the first ; or - and then anything up to the end of string:

res = "abc-xyz;".replaceAll("(?s)[;-].*$", "");
System.out.println(res);

See IDEONE demo

Upvotes: 0

Avinash Raj
Avinash Raj

Reputation: 174706

Just use a negated char class.

^[^-;]*

ie.

Pattern p = Pattern.compile("^[^-;]*");
Matcher m = p.matcher(str);
while(m.find()) {
System.out.println(m.group());
}

This would match any character at the start but not of - or ;, zero or more times.

Upvotes: 6

x squared
x squared

Reputation: 3354

This should do what you are looking for:

[^-;]*

It matches characters that are not - or ;.

Tipp: If you don't feel sure with regular expressions there are great online solutions to test your input, e.g. https://regex101.com/

Upvotes: 0

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