This ProBuilder code snippet demonstrates how to use arrays to compare the values of an indicator (RSI in this case) within the same bar. The code aims to track changes in the RSI value during the formation of a single bar and changes the color of displayed text based on whether the RSI value is increasing or decreasing.

defparam drawonlastbaronly=true
a = rsi[14]
if a > $var[barindex] then
    $var[barindex]=a
    r=0
    g=255
elsif a < $var[barindex] then
    $var[barindex]=a
    r=255
    g=0
endif
drawtext("#a#",barindex,50,dialog,bold,20) coloured(r,g,0)
return a

Explanation of the code:

• defparam drawonlastbaronly=true: This line ensures that the drawing operations (like text) are only performed on the last (most recent) bar, optimizing performance.
• a = rsi[14]: The variable a is assigned the value of the 14-period Relative Strength Index (RSI).
• if a > $var[barindex]: This condition checks if the current RSI value is greater than the previously stored value in the array $var at the index corresponding to the current bar.
• $var[barindex]=a: Updates the array $var at the current bar index with the new RSI value if the condition is true.
• r=0 and g=255: Sets the color of the text to green (no red, full green, no blue) if the current RSI is higher than the previous value.
• elsif a < $var[barindex]: This condition checks if the current RSI value is less than the previously stored value.
• r=255 and g=0: Sets the color of the text to red (full red, no green, no blue) if the current RSI is lower than the previous value.
• drawtext("#a#",barindex,50,dialog,bold,20) coloured(r,g,0): Draws the value of a on the chart at the specified bar index and vertical position (50) with the determined color. The text is bold and size 20.

This code is useful for visualizing how the value of an indicator changes within the same bar, providing immediate visual feedback on the indicator's dynamics.