How to Remove substring from string

Question

I wan't to remove Y from X and this compiles, however when I run it in my main method I get an error saying out of bounds. I am unsure what is wrong. any help would be appreciated.

public static String filter(String X, String Y) {
    String i = X;
    if ((X != null) && (X.length() >0) && (Y != null) &&Y.length() >0 && (i !=null)){
        int z = X.indexOf(Y);
        i = X.substring(0, z) +X.substring(z + Y.length());
    }
    return i;
}

Answer 1

As @singhakash already pointed out that

int z = X.indexOf(Y); --> this is returning -1

So

X.substring(0, z) 

become

X.substring(0, -1)

causing OutOfBounds Exception

PS Why have you complicated it so much !! Instead you can use String#replace or String#replaceAll

String X="StackOverflow";
String Y="flow";
X=X.replaceAll(Y,"");
System.out.println(X);

Output

StackOver

Demo1 - if y is not present in x you get index out of bound

Demo2 - if y is present in x you will get correct output

Answer 2

Use replaceAll method

public static String filter(String X, String Y) {
    return X.replaceAll(Y,"");
}

Answer 3

I guess this will work for you :

if((x !=null && y !=null) && x.contains(y)) {
   System.out.println(x.replaceAll(y, ""));
}

Answer 4

The Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -1 occurs when the length of string X is less than string Y because of this X.substring(z + Y.length())

Have a additional check for "X.length() > Y.length()" and it should work fine.

Answer 5

If You want to remove all occurrence of Y in X use the following code.

public static String filter(String X, String Y) {
if ((X != null) && (X.length() >0) && (Y != null) &&Y.length() >0) {
while(X.contains(Y)){
int z = X.indexOf(Y);
X = X.substring(0, z) +X.substring(z + Y.length());
}}
return X;

also if X does not contain Y then int z = X.indexOf(Y); --> this is returning -1 X.substring(0, z) ie X.substring(0, -1) -->causing OutOfBounds Exception

It is better to use X=X.replaceAll(Y,"");

Answer 6

You can use this:

String subString = testString.subString(firstIndex, secondIndex);

and you can get the index by this:

int index = testString.indexOf(String);