Version 5.0.13

system/Math/Number.php

@@ -540,6 +540,55 @@ class Number implements JsonSerializable
 		return $result;
 	}
 
+	/**
+	 * Get the moving average series from a series of numbers
+	 *
+	 * @param number[] $numbers
+	 * @param int $degree   How many elements of the source $numbers to average over
+	 * @param float $weightIncrement    How much to scale the weight of each value in the moving average as it approaches the current date. The weight starts at 1 and will be multiplied by this number
+	 * @return (number|null)[]      If the input array contains non-numeric values, these will be omitted from the moving average. If there are no numbers in the average period, null is added to the output array instead of a number
+	 */
+	public static function movingAverage( array $numbers, int $degree=5, float $weightIncrement=1 ) : array
+	{
+		if ( count( $numbers ) <= 1 OR $degree <= 1 )
+		{
+			return [...$numbers];
+		}
+
+		$final = [];
+		$values = array_values( $numbers );
+		$keys = array_keys( $numbers );
+		for ( $i = 1; $i < count( $numbers ); $i++ )
+		{
+			$start = max(0, $i - $degree);
+			$slice = array_slice( $values, $start, $i + 1 - $start );
+			$sum = 0;
+			$count = 0;
+			$weight = 1;
+			foreach ( $slice as $number )
+			{
+				if ( !is_numeric( $number ) )
+				{
+					continue;
+				}
+
+				$number = ( is_int( $number ) or is_float( $number ) ) ? $number : (float) $number;
+				$sum += $number * $weight;
+				$count += $weight;
+				$weight *= $weightIncrement;
+			}
+
+			if ( $count === 0 )
+			{
+				$final[$keys[$i]] = null;
+				continue;
+			}
+			$final[$keys[$i]] = $sum / $count;
+		}
+
+		return $final;
+	}
+
 	/**
 	 * Get product of numbers
 	 *