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new 3e50a7f9c Find NaN in ArrayUtils.lastIndexOf for double and float
arrays (#1718)
3e50a7f9c is described below
commit 3e50a7f9cf103357d781483d41ec9c9386e69e9d
Author: alhuda <[email protected]>
AuthorDate: Sat Jun 20 16:30:37 2026 +0530
Find NaN in ArrayUtils.lastIndexOf for double and float arrays (#1718)
* find NaN in ArrayUtils.lastIndexOf for double and float arrays
* Add lastIndexOf tests for positive and negative infinity
---
.../java/org/apache/commons/lang3/ArrayUtils.java | 28 +++++++++++++++-
.../org/apache/commons/lang3/ArrayUtilsTest.java | 38 ++++++++++++++++++++++
2 files changed, 65 insertions(+), 1 deletion(-)
diff --git a/src/main/java/org/apache/commons/lang3/ArrayUtils.java
b/src/main/java/org/apache/commons/lang3/ArrayUtils.java
index 4b6b2cf0b..3a7dafb80 100644
--- a/src/main/java/org/apache/commons/lang3/ArrayUtils.java
+++ b/src/main/java/org/apache/commons/lang3/ArrayUtils.java
@@ -4265,6 +4265,9 @@ public static int lastIndexOf(final double[] array, final
double valueToFind, fi
* @return the last index of the value within the array, {@link
#INDEX_NOT_FOUND} ({@code -1}) if not found or {@code null} array input.
*/
public static int lastIndexOf(final double[] array, final double
valueToFind, int startIndex) {
+ if (Double.isNaN(valueToFind)) {
+ return lastIndexOfNaN(array, startIndex);
+ }
if (isEmpty(array) || startIndex < 0) {
return INDEX_NOT_FOUND;
}
@@ -4296,6 +4299,9 @@ public static int lastIndexOf(final double[] array, final
double valueToFind, in
* @return the last index of the value within the array, {@link
#INDEX_NOT_FOUND} ({@code -1}) if not found or {@code null} array input.
*/
public static int lastIndexOf(final double[] array, final double
valueToFind, int startIndex, final double tolerance) {
+ if (Double.isNaN(valueToFind)) {
+ return lastIndexOfNaN(array, startIndex);
+ }
if (isEmpty(array) || startIndex < 0) {
return INDEX_NOT_FOUND;
}
@@ -4347,8 +4353,10 @@ public static int lastIndexOf(final float[] array, final
float valueToFind, int
if (startIndex >= array.length) {
startIndex = array.length - 1;
}
+ final boolean searchNaN = Float.isNaN(valueToFind);
for (int i = startIndex; i >= 0; i--) {
- if (valueToFind == array[i]) {
+ final float element = array[i];
+ if (valueToFind == element || searchNaN && Float.isNaN(element)) {
return i;
}
}
@@ -4535,6 +4543,24 @@ public static int lastIndexOf(final short[] array, final
short valueToFind, int
return INDEX_NOT_FOUND;
}
+ /**
+ * Finds the last index of the NaN value in a double array.
+ * @param array the array to traverse backwards for NaN, may be {@code
null}.
+ * @param startIndex the start index to traverse backwards from.
+ * @return the last index of the NaN value within the array, {@link
#INDEX_NOT_FOUND} ({@code -1}) if not found or {@code null} array input.
+ */
+ private static int lastIndexOfNaN(final double[] array, final int
startIndex) {
+ if (isEmpty(array) || startIndex < 0) {
+ return INDEX_NOT_FOUND;
+ }
+ for (int i = Math.min(startIndex, array.length - 1); i >= 0; i--) {
+ if (Double.isNaN(array[i])) {
+ return i;
+ }
+ }
+ return INDEX_NOT_FOUND;
+ }
+
/**
* Maps elements from an array into elements of a new array of a given
type, while mapping old elements to new elements.
*
diff --git a/src/test/java/org/apache/commons/lang3/ArrayUtilsTest.java
b/src/test/java/org/apache/commons/lang3/ArrayUtilsTest.java
index a096e949f..b9faef8c4 100644
--- a/src/test/java/org/apache/commons/lang3/ArrayUtilsTest.java
+++ b/src/test/java/org/apache/commons/lang3/ArrayUtilsTest.java
@@ -1824,6 +1824,27 @@ void testLastIndexOfDouble() {
assertEquals(-1, ArrayUtils.lastIndexOf(array, 99));
}
+ @Test
+ void testLastIndexOfDoubleNaN() {
+ final double[] array = { Double.NaN, Double.NEGATIVE_INFINITY,
Double.NaN, Double.POSITIVE_INFINITY };
+ assertEquals(2, ArrayUtils.lastIndexOf(array, Double.NaN));
+ assertEquals(2, ArrayUtils.lastIndexOf(array, Double.NaN, (double) 0));
+ assertEquals(0, ArrayUtils.lastIndexOf(array, Double.NaN, 1));
+ assertEquals(0, ArrayUtils.lastIndexOf(array, Double.NaN, 1, (double)
0));
+ assertEquals(-1, ArrayUtils.lastIndexOf(array, Double.NaN, -1));
+ }
+
+ @Test
+ void testLastIndexOfDoubleInfinity() {
+ final double[] array = { Double.POSITIVE_INFINITY,
Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY };
+ assertEquals(2, ArrayUtils.lastIndexOf(array,
Double.POSITIVE_INFINITY));
+ assertEquals(3, ArrayUtils.lastIndexOf(array,
Double.NEGATIVE_INFINITY));
+ assertEquals(0, ArrayUtils.lastIndexOf(array,
Double.POSITIVE_INFINITY, 1));
+ assertEquals(1, ArrayUtils.lastIndexOf(array,
Double.NEGATIVE_INFINITY, 2));
+ assertEquals(2, ArrayUtils.lastIndexOf(array,
Double.POSITIVE_INFINITY, array.length, (double) 0));
+ assertEquals(1, ArrayUtils.lastIndexOf(array,
Double.NEGATIVE_INFINITY, 2, (double) 0));
+ }
+
@Test
void testLastIndexOfDoubleTolerance() {
double[] array = null;
@@ -1884,6 +1905,23 @@ void testLastIndexOfFloat() {
assertEquals(-1, ArrayUtils.lastIndexOf(array, 99));
}
+ @Test
+ void testLastIndexOfFloatNaN() {
+ final float[] array = { Float.NaN, Float.NEGATIVE_INFINITY, Float.NaN,
Float.POSITIVE_INFINITY };
+ assertEquals(2, ArrayUtils.lastIndexOf(array, Float.NaN));
+ assertEquals(0, ArrayUtils.lastIndexOf(array, Float.NaN, 1));
+ assertEquals(-1, ArrayUtils.lastIndexOf(array, Float.NaN, -1));
+ }
+
+ @Test
+ void testLastIndexOfFloatInfinity() {
+ final float[] array = { Float.POSITIVE_INFINITY,
Float.NEGATIVE_INFINITY, Float.POSITIVE_INFINITY, Float.NEGATIVE_INFINITY };
+ assertEquals(2, ArrayUtils.lastIndexOf(array,
Float.POSITIVE_INFINITY));
+ assertEquals(3, ArrayUtils.lastIndexOf(array,
Float.NEGATIVE_INFINITY));
+ assertEquals(0, ArrayUtils.lastIndexOf(array, Float.POSITIVE_INFINITY,
1));
+ assertEquals(1, ArrayUtils.lastIndexOf(array, Float.NEGATIVE_INFINITY,
2));
+ }
+
@Test
void testLastIndexOfFloatWithStartIndex() {
float[] array = null;
