Case Insensitive String Array Comparison

Question

I am coding in Java and I understand well that I can compare most arrays with Arrays.equals, and I can compare strings case insensitively with String.equalsIgnoreCase, but is there a way to specifically compare Arrays of strings case insensitively?

sample code:

class Foo {
    String[] array; // don't care about case

    @Override
    public boolean equals(Foo obj) {
        // bunch of stuff to check equality
        if (!Arrays.equals(array, obj.array)) return false; // case insensitive?
        return true;
    }
}

You'll have to do it yourself, using a loop. Should be faster than asking the question. — JB Nizet, Nov 24 '14 at 07:39
u can use this link http://stackoverflow.com/questions/15269723/array-contains-without-case-sensitive-lookup — Shriram, Nov 24 '14 at 07:40
Based on what you said you know... loop over the arrays simultaneously and use `String.equalsIgnoreCase` on each element — nem035, Nov 24 '14 at 07:40
May be helpful - http://stackoverflow.com/questions/13817413/something-like-equalsignorecase-while-using-indexof — Subhrajyoti Majumder, Nov 24 '14 at 07:40

score 1 · Accepted Answer · answered Nov 24 '14 at 07:46

Your code wont compile as you are not overriding the Object's equals method which has signature like public boolean equals(Object obj)

Also to do comparison, you could do the following in your modified equals as below:

if (array == foo.array) {
    return true;
}

if (array == null || foo.array == null) {
    return false;
}

int length = array.length;

if (foo.length != length)
        return false;

    for (int i=0; i<length; i++) {
        String string1 = array[i];
        String string2 = foo.array[i];
        if (!(string1==null ? string2==null : string1.equalsIgnoreCase(string2)))
            return false;
    }
return true;

score 1 · Answer 2 · answered Nov 24 '14 at 07:52

For things like that I keep a Utility class where i define a static comparator method (as String[] case insensitive comparison is not a Type specific logic and can be reused somewhere else in the program).

public static boolean caseInsensitiveCompare(String[] array1, String[] array2) {
    // validate arguments
    condition(allNotNullOrEmpty(array1) && allNotNullOrEmpty(array2));

    if (array1 == array2) return true;
    if (array1.length != array2.length) return false;

    for (int i = 0; i < array1.length; i++) {
        if (!array1[i].equalsIgnoreCase(array2[i])) return false;
    }

    return true;
}

P.S. instead of writing this

if (!Arrays.equals(array, obj.array)) return false; // case insensitive?
    return true;

write this

return !Arrays.equals(array, obj.array);

or use Intellij :)

Case Insensitive String Array Comparison

2 Answers2