This code snippet demonstrates how to calculate the highest and lowest values of an Exponential Moving Average (EMA) since the last trade using the ProBuilder language. It ensures that there are enough bars to perform the calculation and that a trade has occurred.

if barindex >= 10 and tradeindex <> 0 then
    EMA=exponentialaverage[10](close)
    HH=highest[barindex-tradeindex](EMA)
    LL=lowest[barindex-tradeindex](EMA)
endif
graph HH as "HighestEMA"
graph LL as "LowestEMA"

Explanation of the Code:

• Conditional Check: The code starts by checking if there are at least 10 bars (`barindex >= 10`) and if at least one trade has occurred (`tradeindex <> 0`). This is crucial to avoid errors in calculating the EMA when there isn’t enough data or no trades have been made.
• Calculating EMA: If the conditions are met, the Exponential Moving Average (EMA) of the last 10 closing prices (`close`) is calculated using exponentialaverage[10](close).
• Finding Highest and Lowest EMA: The highest (`HH`) and lowest (`LL`) values of the EMA since the last trade are then calculated. This is done by using the highest[barindex-tradeindex](EMA) and lowest[barindex-tradeindex](EMA) functions, which look back from the current bar to the bar of the last trade.
• Graphing Results: Finally, the highest and lowest EMAs are graphed with labels “HighestEMA” and “LowestEMA” respectively, allowing for visual representation of these values over time.

This snippet is particularly useful for traders or analysts who want to track the volatility or stability of prices since the last trade by observing the extremes of a moving average indicator.