Operations on arrays, primitive arrays (like int[]
) and
* primitive wrapper arrays (like Integer[]
).
This class tries to handle null
input gracefully.
* An exception will not be thrown for a null
* array input. However, an Object array that contains a null
* element may throw an exception. Each method documents its behaviour.
-1
.
* This value is returned by methods in this class and can also be used in comparisons with values returned by
* various method from {@link java.util.List}.
*/
public static final int INDEX_NOT_FOUND = -1;
// float IndexOf
//-----------------------------------------------------------------------
/**
* Finds the index of the given value in the array.
* *This method returns {@link #INDEX_NOT_FOUND} (-1
) for a null
input array.
null
* @param valueToFind the value to find
* @return the index of the value within the array,
* {@link #INDEX_NOT_FOUND} (-1
) if not found or null
array input
*/
public static int indexOf(float[] array, float valueToFind) {
return indexOf(array, valueToFind, 0);
}
/**
* Finds the index of the given value in the array starting at the given index.
* *This method returns {@link #INDEX_NOT_FOUND} (-1
) for a null
input array.
A negative startIndex is treated as zero. A startIndex larger than the array
* length will return {@link #INDEX_NOT_FOUND} (-1
).
null
* @param valueToFind the value to find
* @param startIndex the index to start searching at
* @return the index of the value within the array,
* {@link #INDEX_NOT_FOUND} (-1
) if not found or null
array input
*/
public static int indexOf(float[] array, float valueToFind, int startIndex) {
if (isEmpty(array)) {
return INDEX_NOT_FOUND;
}
if (startIndex < 0) {
startIndex = 0;
}
for (int i = startIndex; i < array.length; i++) {
if (valueToFind == array[i]) {
return i;
}
}
return INDEX_NOT_FOUND;
}
/**
* Finds the last index of the given value within the array.
* *This method returns {@link #INDEX_NOT_FOUND} (-1
) for a null
input array.
null
* @param valueToFind the object to find
* @return the last index of the value within the array,
* {@link #INDEX_NOT_FOUND} (-1
) if not found or null
array input
*/
public static int lastIndexOf(float[] array, float valueToFind) {
return lastIndexOf(array, valueToFind, Integer.MAX_VALUE);
}
/**
* Finds the last index of the given value in the array starting at the given index.
* *This method returns {@link #INDEX_NOT_FOUND} (-1
) for a null
input array.
A negative startIndex will return {@link #INDEX_NOT_FOUND} (-1
). A startIndex larger than the
* array length will search from the end of the array.
null
* @param valueToFind the value to find
* @param startIndex the start index to travers backwards from
* @return the last index of the value within the array,
* {@link #INDEX_NOT_FOUND} (-1
) if not found or null
array input
*/
public static int lastIndexOf(float[] array, float valueToFind, int startIndex) {
if (isEmpty(array)) {
return INDEX_NOT_FOUND;
}
if (startIndex < 0) {
return INDEX_NOT_FOUND;
} else if (startIndex >= array.length) {
startIndex = array.length - 1;
}
for (int i = startIndex; i >= 0; i--) {
if (valueToFind == array[i]) {
return i;
}
}
return INDEX_NOT_FOUND;
}
/**
* Checks if the value is in the given array.
* *The method returns false
if a null
array is passed in.
true
if the array contains the object
*/
public static boolean contains(float[] array, float valueToFind) {
return indexOf(array, valueToFind) != INDEX_NOT_FOUND;
}
/**
* Checks if an array of primitive doubles is empty or null
.
true
if the array is empty or null
* @since 2.1
*/
public static boolean isEmpty(float[] array) {
if (array == null || array.length == 0) {
return true;
}
return false;
}
}