CODEWITHSUNDEEP
javaregexstringsplit
Buccaneer
Buccaneer

Reputation: 141

java split string and only keep everything after a particular word

I have a string that I need to split

SELECT a, b, c FROM X....

I need to split it and only keep, "FROM...." and onwards. Right now I have this, but I think it will actually get rid of the FROM string also correct?

String query = xyz.getQuery();
String [] newQuery = query.split("FROM");
String splitQuery = newQuery[1];

Upvotes: 1

Views: 1419

Answers (3)

jam
jam

Reputation: 1293

In addition with split and possitive lookahead, so you don't get rid of "FROM". 

@Test
public void testRegex(){

    String query = "SELECT a, b, c FROM x y z";
    String regex = "(?=FROM.*)|(?=from.*)";
    System.out.println(query.split(regex)[1]);

    assertEquals("FROM x y z", query.split(regex)[1]);
}

FROM x y z

Upvotes: 0

rock321987
rock321987

Reputation: 11032

Why exactly do you need regex for this?

without regex

Sol 1

Add this to your code

String splitQuery = "FROM " + newQuery[1];

Sol 2

System.out.println(line.substring(line.indexOf("FROM")));

and if you still need regex

String line = "SELECT a, b, c FROM X....";
String pattern = "((FROM|from).*)";
Pattern r = Pattern.compile(pattern);
Matcher m = r.matcher(line);

if (m.find()) {
     System.out.println("Found value: " + m.group(0));
}

Upvotes: 2

Shababb Karim
Shababb Karim

Reputation: 3703

Instead of splitting, you could try this. Assuming you only want what is written after the first FROM and not from any nested FROM:

import java.util.regex.Matcher;
import java.util.regex.Pattern;


public class Solution {


    public String getSubString(String s)
    {
        Pattern p = Pattern.compile("FROM.+");
        Matcher m = p.matcher(s);

        if(m.find())
        {
            return m.group(0);
        }

        return null;
    }

    public static void main(String[] args) {

        String query = "SELECT a, b, c FROM myTable";
        Solution sol = new Solution();

        String ans = sol.getSubString(query);

        if(ans != null)
        {
            System.out.println(ans);
        }
        else
        {
            System.out.println("Not Found");
        }
    }
}

Aside from this a better way is to first get the starting position of FROM and then simply use substring method from that point to length of the string.

Upvotes: 0

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