Returns a series containing difference between a value in the original series and a value at the specified offset. For example, calling `Series.diff 1 s` returns a series where previous value is subtracted from the current one. In pseudo-code, the function behaves as follows: result[k] = series[k] - series[k - offset] ## Parameters - `offset` - When positive, subtracts the past values from the current values; when negative, subtracts the future values from the current values. - `series` - The input series, containing values that support the `-` operator. [category:Series transformations]

public static Series<K, T> Diff<K, T>(
	int offset,
	Series<K, T> series
)