Does Java have a IN operator or function like SQL duplicate

Question

I want to know if there's a way of doing something like this in Java :

if(word in stringArray) {
  ...
}

I know I can make a function for this but I just want to know if Java has already something for this.

Thank you!

Answer 1

The Java language is designed to be powerful but also simple. There is no such operator in Java at the language level, but certainly libraries have been written to facilitate such queries.

If you want to know if some object is a member of some set of objects, then instead of an array, you should use -- what else? -- a Set. These data structures naturally allows such queries, and better yet, they're optimized for such queries.

You can easily check if a given string is in a Set<String> like this:

    String[] arr = { "Alice", "Bob", "Carol" };
    Set<String> names = new HashSet<String>(Arrays.asList(arr));

    System.out.println(names.contains("Alice")); // true
    System.out.println(names.contains("Dean")); // false

Using a HashSet, contains is a constant-time operation. This is much better than a linear search through an array.

You should familiarize yourself with what data structures are made available for you by the Java Collections Framework. They allow you to write codes that are idiomatic, maintainable, flexible, and supported by many of the powerful algorithms available for these data structures.

In SQL

x in ('Alice', 'Bob', 'Carol')

In Java:

Arrays.asList("Alice", "Bob", "Carol").contains(x)

Hope this helps!

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Thanks!