Returns a frame with columns containing difference between an original value and a value at the specified offset. For example, calling `Frame.diff 1 s` returns a frame where previous column values is subtracted from the current ones. In pseudo-code, the function behaves as follows: result[k] = series[k] - series[k - offset] Columns that cannot be converted to `float` are left without a change. ## Parameters - `offset` - When positive, subtracts the past values from the current values; when negative, subtracts the future values from the current values. - `frame` - The input frame containing at least some `float` columns. [category:Frame transformations]

public static Frame<R, C> Diff<R, C>(
	int offset,
	Frame<R, C> frame
)