Value of analyisis technique parameter, that have DoubleSeries type can be specified using expressions.

Each expression can consist of the following:

- Mathematical expressions (+, -, *, /, etc.)
- Calls to Math class methods (e.g. Math.Abs(Close[0])). See Math Class Methods.
- Open - open price of bar (example: Open[2] - open of 3rd bar back)
- High - high price of bar (example: High[0] - high of current bar)
- Low - low price of bar (example: Low[0] - low of current bar)
- Close - close price of bar (example: Close[0] - close of current bar)
- Volume - volume of bar (example: Volume[0] - volume of current bar)
- O - open price of current bar
- H - high price of current bar
- L - low price of current bar
- C - close price of current bar
- V - volume of current bar

**Example.**

Expression to calculate analysis technique on average of high and low of previous bar:

(High[1] + Low[1]) /2

See also Formatting Indicator, Formatting Strategy,Analysis Technique Parameters.