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];
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));
}
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.
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
indexOfandsubstring?