[java] Iterating through array - java

I was wondering if it was better to have a method for this and pass the Array to that method or to write it out every time I want to check if a number is in the array.

For example:

public static boolean inArray(int[] array, int check) {

    for (int i = 0; i < array.length; i++) {
        if (array[i] == check) 
            return true;
    }

    return false;
}

Thanks for the help in advance!

Using java 8 Stream API could simplify your job.

public static boolean inArray(int[] array, int check) {
    return Stream.of(array).anyMatch(i -> i == check);
}

It's just you have the overhead of creating a new Stream from Array, but this gives exposure to use other Stream API. In your case you may not want to create new method for one-line operation, unless you wish to use this as utility. Hope this helps!

You can import the lib org.apache.commons.lang.ArrayUtils

There is a static method where you can pass in an int array and a value to check for.

contains(int[] array, int valueToFind) Checks if the value is in the given array.

ArrayUtils.contains(intArray, valueToFind);

ArrayUtils API

If you are using an array (and purely an array), the lookup of "contains" is O(N), because worst case, you must iterate the entire array. Now if the array is sorted you can use a binary search, which reduces the search time to log(N) with the overhead of the sort.

If this is something that is invoked repeatedly, place it in a function:

private boolean inArray(int[] array, int value)
{  
     for (int i = 0; i < array.length; i++)
     {
        if (array[i] == value) 
        {
            return true;
        }
     }
    return false;  
}  

Since atleast Java 1.5.0 (Java 5) the code can be cleaned up a bit. Arrays and anything that implements Iterator (e.g. Collections) can be looped as such:

public static boolean inArray(int[] array, int check) {
   for (int o : array){
      if (o == check) {
         return true;
      }
   }
   return false;
}

In Java 8 you can also do something like:

// import java.util.stream.IntStream;

public static boolean inArray(int[] array, int check) {
   return IntStream.of(array).anyMatch(val -> val == check);
}

Although converting to a stream for this is probably overkill.