remove the last part of a string in java

String Y="part1 part2 part3",X="part1";

boolean foundMatch = false;
while(!foundMatch) {
    foundMatch = Y.equals(X);
    if(foundMatch) {
        break;
    }
    else {
        Y = useSplitToRemoveLastPart(Y);
        if(Y.equals("")) {
 开发者_JAVA百科           break;
        }
    }

//implementation of useSplitToRemoveLastPart()

private static String useSplitToRemoveLastPart(String y) {

  //What goes here .. It should chop the last part of the string..
return null;

 }

Can anyone help ...

If you want part3 to be removed and provided that all the words are separated by space

String str ="part1 part2 part3";

String result = str.substring(0,str.lastIndexOf(" "));

If you really want to use split:

private static String useSplitToRemoveLastPart(String str) {
    String[] arr = str.split(" ");
    String result = "";
    if (arr.length > 0) {
        result = str.substring(0, str.lastIndexOf(" " + arr[arr.length-1]));
    }
    return result;

}

Your whole code can be optimized to:

boolean foundmatch = y.startsWith(x);
y = foundmatch? x : "";

public String removeLastSubstring(String target, String toRemove){
    int idx = target.lastIndexOf(toRemove);
    target = target.substring(0, idx) + target.substring(idx + toRemove.length());
    return target;
}

You only need to pass it your target and the LAST substring you want to remove, example:

String s = "123 #abc# 456";
s = removeLastSubstring(s, "#abc#");

If you want to do it using split, then you can do:

String s[] = Y.split(" ");
String n = "";
for (int i = 0; i < s.length - 1; i++)
        n+= s[i];
return n;

By the way, If the method you need to build is called useSplitToRemoveLastPart(String t), then I'd suggest you to use split to remove last part.

Take a look here.