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Using Data

Types

Data Types

HaasScript uses various data types to store and manipulate different kinds of information. Understanding these types is essential for writing correct and efficient trading strategies.

Overview of HaasScript Data Types

HaasScript automatically determines variable types based on the assigned value. The main types you'll work with are:

  • Numbers - Numeric values (integers and decimals)
  • Strings - Text values
  • Booleans - true/false values
  • Collections - Arrays of numeric data
  • Signals - Trading signal constants
  • Enums - Predefined constant values

Numbers

Numbers represent numeric values and can be integers or decimals.

Integers

Whole numbers without decimal points:

local rsiPeriod = 14
local quantity = 100
local count = 0

Decimals

Numbers with decimal points for precise calculations:

local price = 45000.50
local stopLossPercent = 2.5
local leverage = 5.0

Scientific Notation

For very large or small numbers:

local veryLarge = 1.5e10   -- 15,000,000,000
local verySmall = 1.5e-10  -- 0.00000000015

Number Operations

local a = 10
local b = 3

-- Basic arithmetic
local sum = a + b           -- 13
local difference = a - b    -- 7
local product = a * b       -- 30
local quotient = a / b      -- 3.333...
local remainder = a % b     -- 1 (modulus)
local power = a ^ b         -- 1000 (10 to the power of 3)

Using Numbers in Trading

-- Indicator parameters
local rsiPeriod = 14
local macdFast = 12
local macdSlow = 26

-- Risk management percentages
local stopLossPercent = 2.0
local takeProfitPercent = 5.0

-- Price calculations
local currentPrice = ClosePrices()  -- Uses latest price
local targetPrice = currentPrice * 1.05  -- 5% above
local stopPrice = currentPrice * 0.98     -- 2% below

Strings

Strings represent text data enclosed in quotes.

String Declaration

-- Single quotes
local text1 = 'Hello'

-- Double quotes
local text2 = "World"

-- Empty string
local empty = ""

String Concatenation

Combine strings using the .. operator:

local greeting = "Hello, " .. "World!"
local market = "BTC_USDT"
local message = "Trading " .. market

-- Concatenating strings with numbers
local rsi = 25.5
local logMessage = "RSI value: " .. rsi  -- "RSI value: 25.5"

Using Strings in Trading

-- Trading reasons
local entryReason = "RSI oversold signal"
local exitReason = "Take profit reached"

-- Log messages
local message = "Entering long position at RSI: " .. rsiValue
Log(message)

-- Market identification
local market = BaseCurrency() .. "_" .. QuoteCurrency()

Booleans

Booleans represent logical values: either true or false.

Boolean Declaration

local inPosition = true
local useStopLoss = false
local isMarketOpen = true

Boolean Operations

local a = true
local b = false

-- AND (both must be true)
local andResult = a and b  -- false

-- OR (at least one must be true)
local orResult = a or b    -- true

-- NOT (reverses the value)
local notResult = not a    -- false

Comparison Operators

Comparisons return boolean values:

local price = 45000
local target = 46000

local isAbove = price > target     -- false
local isBelow = price < target     -- true
local isEqual = price == target    -- false
local notEqual = price ~= target   -- true
local greaterOrEqual = price >= target  -- false
local lessOrEqual = price <= target    -- true

Using Booleans in Trading

-- Position state
local hasLongPosition = HasLongPosition()
local hasShortPosition = HasShortPosition()

-- Strategy conditions
local isOversold = rsi < 30
local isOverbought = rsi > 70
local trendIsUp = fastMA > slowMA

-- Combine conditions
local buySignal = isOversold and trendIsUp
local sellSignal = isOverbought or (rsi > 60 and trendIsDown)

if buySignal then
    DoLong("Multiple indicators confirm buy")
end

Collections (HaasNumberCollection)

Collections are arrays of numeric data that store historical values. They are the most common data type you'll work with in HaasScript.

What are Collections?

Collections store multiple numeric values in sequence, typically representing time-series data like prices, volumes, or indicator values.

local closePrices = ClosePrices()  -- Collection of closing prices
local highPrices = HighPrices()    -- Collection of high prices
local lowPrices = LowPrices()      -- Collection of low prices
local volume = Volume()            -- Collection of volume data

Accessing Collection Values

HaasScript collections use 1-based indexing where:

  • Index 1 = Latest value (most recent candle)
  • Index N = Oldest value (N candles ago)
local closePrices = ClosePrices()

-- Access specific values
local latestClose = closePrices[1]    -- Most recent closing price
local previousClose = closePrices[2]  -- Previous candle closing price
local tenCandlesAgo = closePrices[10] -- Price 10 candles ago

Important: Never use index 0 - it does not exist in HaasScript's 1-based indexing.

Automatic Value Usage

When you use a collection in a number context, HaasScript automatically uses the latest value (index 1):

local closePrices = ClosePrices()

-- These are equivalent:
local currentPrice = closePrices      -- Uses latest value
local currentPrice2 = closePrices[1]  -- Explicitly uses latest value

-- Works in calculations
local avgPrice = (closePrices + highPrices + lowPrices) / 3

Collection Operations

Many HaasScript functions work directly with collections:

-- Indicators accept collections
local rsi = RSI(ClosePrices(), 14)        -- Uses closePrices collection
local sma = SMA(HighPrices(), 20)          -- Uses highPrices collection
local macd = MACD(ClosePrices(), 12, 26, 9) -- Uses closePrices collection

-- Math operations
local avgPrice = (ClosePrices() + HighPrices()) / 2

-- Length of collection
local candleCount = Count(ClosePrices())  -- Number of candles in data

Collections in Custom Commands

When defining parameters for custom commands, use ListNumberType for collections:

DefineCommand("MyIndicator", "Custom indicator")

local prices = DefineParameter(ListNumberType, 'prices', 'Price data', true, ClosePrices())
local period = DefineParameter(NumberType, 'period', 'Period', true, 14)

-- Your logic here

Common Collection Mistakes

local closePrices = ClosePrices()

-- Wrong: Trying to access index 0 (doesn't exist)
local value = closePrices[0]  -- Error!

-- Wrong: Using .Value property (doesn't exist)
local value = closePrices.Value  -- Error!

-- Correct: Use index 1 for latest value
local latest = closePrices[1]

-- Correct: Use collection directly (auto-uses latest)
local latest = closePrices

Signals

Signals are special constants used for trading decisions.

Signal Types

-- Entry signals
SignalLong           -- Enter long position
SignalShort          -- Enter short position
SignalNone           -- No signal

-- Exit signals
SignalExitLong       -- Exit long position
SignalExitShort      -- Exit short position
SignalExitPosition   -- Exit any position

Using Signals in Trading

local rsi = RSI(ClosePrices(), 14)
local signal = SignalNone

-- Determine signal based on conditions
if rsi < 30 then
    signal = SignalLong
elseif rsi > 70 then
    signal = SignalShort
else
    signal = SignalNone
end

-- Execute the signal
DoSignal(signal)

Signal Functions

-- Direct signal execution
DoLong("Entry reason")
DoShort("Entry reason")
DoExitPosition("Exit reason")

-- Signal-based execution
if condition then
    DoSignal(SignalLong)
end

Enums

Enums (enumerations) are predefined constant values used throughout HaasScript.

Common Enums

HaasScript uses enums for various settings:

-- Time intervals
Minute1, Minute5, Minute15, Minute30, Hour1, Hour4, Hour12, Day1, Week1

-- Order types
Limit, Market

-- Position sides
Long, Short

-- And many more defined in HaasScript

Using Enums

-- Set chart interval
SetCurrentInterval(Minute15)

-- Order type selection
local orderType = Market  -- or Limit

-- Position side checks
if HasLongPosition() then
    -- Long position logic
end

Type Conversions

HaasScript automatically handles many type conversions, but understanding them helps avoid errors.

Number to String

local rsi = 25.5
local message = "RSI: " .. rsi  -- Automatically converts to string

String to Number

local text = "14.5"
local number = tonumber(text)  -- Converts to number: 14.5

local invalid = "abc"
local result = tonumber(invalid)  -- Returns nil (not a number)

Boolean to Number

local flag = true
local numberValue = flag and 1 or 0  -- true = 1, false = 0

Collection to Number

local closePrices = ClosePrices()

-- When used in number context, uses latest value
local currentPrice = closePrices  -- Same as closePrices[1]

Type Checking

Check variable types when needed:

local value = 100

-- Check if number
if type(value) == "number" then
    Log("Value is a number")
end

-- Check if string
if type(value) == "string" then
    Log("Value is a string")
end

-- Check if nil
if value == nil then
    Log("Value is nil")
end

Common Type Mistakes

Type Mismatch in Operations

-- Error: Can't concatenate boolean directly
local isActive = true
local message = "Status: " .. isActive  -- Error!

-- Correct: Convert to string or use text
local isActive = true
local message = "Status: " .. tostring(isActive)  -- "Status: true"

Incorrect Collection Access

local closePrices = ClosePrices()

-- Error: Index 0 doesn't exist
local value = closePrices[0]

-- Error: .Value property doesn't exist
local value = closePrices.Value

-- Correct: Use index 1 or collection directly
local latest = closePrices[1]
local latest2 = closePrices

Mixing Types in Comparisons

local number = 100
local text = "100"

-- These are NOT equal
if number == text then  -- This is false!
    Log("They are equal")
end

-- Correct: Convert to same type first
if tostring(number) == text then
    Log("They are equal")
end

Best Practices

  1. Use appropriate types for the data you're storing
  2. Let HaasScript infer types rather than declaring them explicitly
  3. Be careful with collections - remember 1-based indexing
  4. Check for nil before using variables that might be empty
  5. Use proper string concatenation when combining text and numbers
  6. Understand auto-conversion - collections automatically use latest value in number contexts
  7. Use signal constants rather than string values for trading signals

Summary

  • Numbers: Integers and decimals for calculations
  • Strings: Text data enclosed in quotes
  • Booleans: true/false for logical conditions
  • Collections: Arrays of data with 1-based indexing, auto-use latest value
  • Signals: Predefined constants for trading decisions
  • Enums: Predefined constants for configuration
  • Type conversions: Automatic in many cases, manual when needed
  • Collections are special: 1-based indexing, index 1 = latest, no .Value property

Understanding data types helps you write correct HaasScript code and avoid common errors related to type mismatches and incorrect data access.

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