Remove the last part of a String in Java

Question

My Code:

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("")) {
            break;
        }
    }

Implementation of useSplitToRemoveLastPart()

private static String useSplitToRemoveLastPart(String y) {
    // What goes here?
    // It should chop the last part of the String...
}

Can anyone help ...

Diaphony

Would you mind to define what "the last part of the string" is? – Cashman

Give a concrete example of a given input and a given output. – Ditty

Answer 1

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(" "));

Clausius

The instructions implicitly require the use of split() which this solution does not. Not going to downvote, because I find this method to be superior (for the real world) but it doesn't meet the requirements set forth by the name of the method. – Zhao

It may not answer the OP, but this is the answer that I, and apparently 10 others, were looking for. Thanks :) – Cerellia

Answer 2

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;

}

Testaceous

Answer 3

Your whole code can be optimized to:

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

Cashman

Answer 4

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#");

Acutance

Answer 5

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;

Welby

I want to +1 for solving OPs problem with the given instruction, but I also want to -1 for encouraging the use of string += otherString in a loop. – Zhao

:) maybe I live in another world, but how do you connect strings? – Welby

StringBuilder sb = new StringBuilder(); for(...) { sb.append(s[i]); } return sb.toString(); – Zhao

Answer 6

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.

Nutting