Question

Hi I was recently developing a code where i had to extract the last 3 group of digits. So i used pattern to extract the data. But i failed to understand. CAN any one help me to understand it ??

    String str ="EGLA 0F 020";
    String def = "ALT 1F 001 TO ALT 1F 029";
    String arr[] = def.split("TO");
    String str2 = arr[0];
    System.out.println("str2:"+str2);
    Pattern pt = Pattern.compile("[0-9][0-9][0-9]$");
    Matcher m1 = pt.matcher(str);
    Matcher m2 = pt.matcher(str2);
    boolean flag = m1.find();
    boolean flag2 = m2.find();
    if(flag)
        System.out.println("first match:::"+m1.group(0));
    else 
        System.out.println("Not found");
    if(flag2)
        System.out.println("first match:::"+m2.group(0));
    else
        System.out.println("Not found");

The output produced for the above code is As follows:::

    str2:ALT 1F 001 
    first match:::020
    Not found

Please Do reply iam stuck here ??

Answer 1

It’s because when you split you have a trailing space.

String str = "EGLA 0F 020";
String str2 = "ALT 1F 001 ";
//                       ^ trailing space

You could fix it a number of ways. For example:

• by splitting on " TO "
• trimming the result
• allowing trailing spaces in your regular expression.

For example, this change would work:

String arr[] = def.split(" TO ");