📖 Definition
The CountIf() function in NinjaScript is a formidable tool that allows traders and programmers to determine how often a certain condition holds true over a defined look-back period in bars. Imagine asking, “Over the past ‘Y’ bars, how many times did ‘X’ happen?” That’s exactly what this function helps discern.
Important: Always remember that this tool is not tailored for multi-series strategies and indicators.
↩️ Method Return Value
Expect an integer (int) when you use the CountIf() function. This integer showcases the number of times the specified condition was met over the period you’ve defined.
🔧 Syntax
CountIf(Func condition, int period)
- condition: Think of this as the rule you’re keen on checking. It boils down to either a ‘true’ or ‘false’.
- period: This is the span, in bars, during which you’re probing the condition.
Pro Tip: If lambda expressions, like the one in “condition”, seem foreign, simply visualize them as concise, bite-sized functions. They make it a breeze to detail a slice of logic directly.
🌟 Examples
1. Counting Up Bars:
// Among the last 10 bars, if 8 were up bars, then we can enter a long position.
if (CountIf(() => Close[0] > Open[0], 10) > 8)
EnterLong();
Here, the check is for bars where the closing is higher than the opening price. A long position is initiated if over 8 such bars surface in the last 10.
2. Bars Above a Moving Average:
// If a 20-period SMA is surpassed by the closing of 7 out of the last 10 bars, take a specific action.
if (CountIf(() => Close[0] > SMA(20)[0], 10) == 7)
// Implement your desired action here.
This instance observes how often the last 10 bars ended above a 20-period simple moving average.
3. Tracing Oversold Conditions:
// Over the last 14 bars, let’s pinpoint how many times the RSI dipped below 30, hinting at a potentially oversold market.
if (CountIf(() => RSI(14)[0] < 30, 14) > 3)
// Here’s a potential buying cue. Tailor your strategy accordingly.
In this illustration, the RSI (Relative Strength Index) aids in detecting potential “oversold” scenarios.
4. Tallying Consecutive Down Bars:
// If a decline is witnessed in all the last 5 bars, perhaps a reversal is on the cards.
if (CountIf(() => Close[0] < Open[0], 5) == 5)
// A bounce back might be imminent. Consider going long.
The above example demonstrates the prowess of CountIf() in counting consecutive occurrences.
🔚 Conclusion
NinjaScript’s CountIf() function stands as a powerful asset for traders aiming to embed more dynamism and condition-centric strategies in their trading algorithms. Knowledge is potent, but applying this knowledge by rigorously back-testing strategies before live trading ensures safety and efficiency.
