Add new formula function arrayIndex (#3333)

Author: tynanford

core/formula/doc/index.rst

@@ -132,6 +132,9 @@ element is defined as array[x] + offset. To subtract, use negative offset.
 or VString at the specified index of the input array. If the index is invalid, a NaN or
 empty string is returned.
 
+**arrayIndex([VNumberArray | VStringArray] array, [VNumber | VString] value)** - Returns the index of the first
+occurrence of the specified value in the input array. If the value is not found, -1 is returned.
+
 **histogramOf(VNumberArray array [, VNumber binCount])** - Computes a histogram for the input array. The binCount
 argument is optional and defaults to 100.
 

core/formula/src/main/java/org/csstudio/apputil/formula/array/ArrayIndexFunction.java

@@ -0,0 +1,72 @@
+package org.csstudio.apputil.formula.array;
+
+import org.epics.util.array.ListNumber;
+import org.epics.vtype.VNumber;
+import org.epics.vtype.VNumberArray;
+import org.epics.vtype.VString;
+import org.epics.vtype.VStringArray;
+import org.epics.vtype.VType;
+import org.epics.vtype.VInt;
+import org.epics.vtype.Alarm;
+import org.epics.vtype.Time;
+import org.epics.vtype.Display;
+import org.phoebus.core.vtypes.VTypeHelper;
+
+import java.util.List;
+
+/**
+ * Get index of the specified element in the array.
+ */
+public class ArrayIndexFunction extends BaseArrayFunction {
+
+    @Override
+    public String getName() {
+        return "arrayIndex";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Returns the index of the specified element in the array, -1 if not found.";
+    }
+
+    @Override
+    public List<String> getArguments() {
+        return List.of("<String | Number> array", "element");
+    }
+
+    /**
+     * Get index of the specified element in the array.
+     * @param args Arguments, count will match <code>getArgumentCount()</code>
+     * @return A {@link VInt} with the index of the element in the array, -1 if not found. If the arguments are not of
+     * the supported types, {@link BaseArrayFunction#DEFAULT_NAN_DOUBLE} or {@link BaseArrayFunction#DEFAULT_EMPTY_STRING}
+     */
+    @Override
+    public VType compute(VType... args) {
+        boolean isStringArray = args[0] instanceof VStringArray;
+        if (isStringArray && args[1] instanceof VString) {
+            VStringArray stringArray = (VStringArray) args[0];
+            VString element = (VString) args[1];
+            List<String> data = stringArray.getData();
+
+            int idx = data.indexOf(element.getValue());
+            return VInt.of(idx, Alarm.none(), Time.now(), Display.none());
+        }
+        else if (VTypeHelper.isNumericArray(args[0]) && args[1] instanceof VNumber) {
+            VNumberArray numberArray = (VNumberArray) args[0];
+            ListNumber data = numberArray.getData();
+            VNumber element = (VNumber) args[1];
+            double elementValue = element.getValue().doubleValue();
+
+            for (int i = 0; i < data.size(); i++) {
+                if (data.getDouble(i) == elementValue) {
+                    return VInt.of(i, Alarm.none(), Time.now(), Display.none());
+                }
+            }
+            // return -1 if not found
+            return VInt.of(-1, Alarm.none(), Time.now(), Display.none());
+        }
+        else {
+            return isStringArray ? DEFAULT_EMPTY_STRING : DEFAULT_NAN_DOUBLE;
+        }
+    }
+}

core/formula/src/main/resources/META-INF/services/org.csstudio.apputil.formula.spi.FormulaFunction

@@ -63,6 +63,7 @@ org.csstudio.apputil.formula.array.ArraySampleWithStrideFunction
 org.csstudio.apputil.formula.array.ArrayStatsFunction
 org.csstudio.apputil.formula.array.ArrayMaxFunction
 org.csstudio.apputil.formula.array.ArrayMinFunction
+org.csstudio.apputil.formula.array.ArrayIndexFunction
 org.csstudio.apputil.formula.array.ArrayCumSumFunction
 
 # Bitwise Operation