Question

I am quite bad at Java Regular expression so I hope you guys will help me.

String variable = "My life is better ";
String variable2 = "My life01 is better";

Now I have to write a code which would return true if the string has only “life”

So I should get TRUE only for variable not for variable2 because it has life but “01” too.

~thanks.

I have tried

if (variable.contains("life")){
System.out.println("TRUE");}

It return TRUE for both.

See solution :

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

public class Test {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Pattern p = Pattern.compile("\\blife\\b");
        Matcher m = p.matcher("life0 is better");
        boolean b = m.find();
        System.out.println(b);

    }


}

Answer 1

Use the following regex: –

"\blife\b"

with Pattern and Matcher class. This will match for complete word. (\b denote word boundary)

You would have to use Matcher#find method, to check whether a string contains this pattern.

---

Note: – If you want to use String.matches, which would be appropriate here, than going with Pattern and Matcher, you would have to add .* in the front and the end. Because, String.matches matches the whole string.

For e.g: –

String str = "asdf life asdf";
System.out.println(str.matches("\\blife\\b"));       // Prints false

System.out.println(str.matches(".*\\blife\\b.*"));  // Prints true

In the second Regex, .* matches the string before and after life.