Does Java have a “IN” operator or function like SQL? [duplicate]

Answer 1

You can use java.util.Collection.contains() for collections. If what you have is a non-null array, you can use java.util.Arrays.asList(array).contains().

Answer 2

If the array is sorted, you can use Arrays.binarySearch to find the data.

Like this:

   if (Arrays.binarySearch(stringArray, word)>=0)  {
     // word found in the array.
   }

If the array is unsorted, commons lang, has the ArrayUtils.indexOf method.

Finally, if you are searching a large array, then a parallel search may be worthwhile using ParallelArray, from JSR166 - coming in Java SE 7 and available now as a download. This article gives an introduction.

Answer 3

In SQL

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

In Java:

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

Answer 4

Without arrays:

public static <T> boolean in(T value, T... list) {
    for (T item : list) {
        if (value.equals(item))
            return true;
    }
    return false;
}

usage:

int val = 1;
assert in(val, 1,2,3,4);

Answer 5

if(myArrayList.contains("hello"))
{
    // yay
}

Answer 6

Java has no "in" operator.

For arrays you need to iterate them and look for a matching item.

For Lists you can use the contains method.