How to compare multiple strings? [duplicate]

Answer 1

You can try using Arrays.asList():

else if (!Arrays.asList("a", "b").contains(question)) {
    ...
}

Answer 2

Two things wrong: You can't just specify multiple values with || (or &&) like that. You need to specify both the left side and the right side explicitly each time.

Second, use equals to compare String values, not the == (or in this case !=) operators. == compares two object references to see if they are the same object.

} else if (!("a".equals(question) || "b".equals(question)))

Or an alternative is to make a temporary List and use contains, which might be clearer for longer lists of things to test:

} else if (!Arrays.asList("a", "b").contains(question))

Answer 3

First of all, don't use == for strings. You'll learn why later. You want to compare strings by their contents, not where they are in memory. In rare cases a string of "a" could compare false to another string called "a".

Second, split it up so you are performing boolean logic on the comparison results:

else if(!(question.equals("a") || question.equals("b")) {

Answer 4

As an aside, you should use equals for objects not ==

To answer your question, you have to repeat the equals call on both sides of the ||

}else if( ! (question.equals("a") || question.equals("b"))  ) {

Answer 5

}else if( !(question.equals("a") || question.equals("b")) {
    System.out.println("Sorry that isn't an A or a B");

You can't do NOT equals a OR b
You have to do NOT(equals a OR equals b)

Secondly, you are comparing strings with !=, but you should be comparing strings using the .equals(String) method. This has been said millions of times, but: == and != are comparing object references, whereas .equals(String) is comparing String values.

Answer 6

String[] options = {"a", "b"}; // Must be sorted.
if (java.util.Arrays.binarySearch(options, question) < 0) {
  System.out.println("Sorry that isn't an A or a B");
}

Alternatively (assuming your strings don't contain |:

if ("a|b".indexOf(question) == -1) {
  System.out.println("Sorry that isn't an A or a B");
}