Variables and Types#

Declaring Variables#

In Pine Script, variables are declared with = and the type is inferred automatically by the compiler:

myLength = 14          // integer (int)
myLevel  = 50.5        // float
mySignal = true        // boolean (bool)
myLabel  = "Breakout"  // string

Once declared, a variable is recalculated and updated on every bar execution.

Types#

Pine Script basic types:

na — Not Available#

na is a Pine Script-specific value representing data that does not exist or has not been defined yet, similar to null or NaN in other languages.

For example, when calculating a 14-period RSI, the first 13 bars don’t have enough data, so the RSI value is na for those bars.

Use the na(x) function to check whether a value is na:

rsiValue = ta.rsi(close, 14)

if na(rsiValue)
    label.new(bar_index, high, "Insufficient data")

var — Persisting Variables Across Bars#

By default, variables are re-initialized on every bar. If you need to accumulate values across bars, declare with the var keyword:

//@version=6
indicator("Volume Accumulation Demo")

// Without var: resets to 0 on every bar, count always equals 1
// count = 0

// With var: initialized to 0 only on the first bar, retains value afterward
var count = 0
count := count + 1  // Use := to update an already-declared variable

plot(count, title="Bar Count")

A var variable’s initial value is assigned only on the first bar; on every subsequent bar it retains the value from the previous bar.

Updating Variable Values#

After declaring a variable, use the := operator to update its value (rather than re-declaring it):

var highestHigh = high  // Initialize

if high > highestHigh
    highestHigh := high  // Update to a higher value

Note: = is for declaration, := is for update. Mixing them causes a compile error.

Series vs. Simple Types#

Pine Script variables have two “qualifiers”:

• series: Each bar has its own independent value; past values are accessible via [N]
• simple / const: A single value that doesn’t change throughout the script’s execution

// series float: different close price on every bar
myClose = close         // series float

// simple int: fixed parameter that doesn't change
length = input.int(14, "Period")  // simple int

In most cases you don’t need to specify this manually — Pine Script infers it automatically. However, some function parameters require a simple type, which means you cannot pass a series value that changes bar by bar.

input — Adjustable Parameters#

Use the input family of functions to create parameters that can be adjusted in the chart UI without modifying the code:

//@version=6
indicator("RSI Indicator")

// Create adjustable parameters
length     = input.int(14, "RSI Period",   minval=1, maxval=100)
overbought = input.int(70, "Overbought",   minval=50, maxval=100)
oversold   = input.int(30, "Oversold",     minval=0,  maxval=50)

rsiValue = ta.rsi(close, length)

plot(rsiValue, "RSI", color=color.purple)
hline(overbought, "Overbought", color=color.red)
hline(oversold,   "Oversold",   color=color.green)

Commonly used input functions:

Type Conversion#

Pine Script handles type conversion automatically in most cases, but sometimes manual conversion is needed:

myInt   = 10
myFloat = float(myInt)          // int → float

myFloat2 = 3.7
myInt2   = int(myFloat2)        // float → int (truncated, result is 3)

myNum    = 42
myStr    = str.tostring(myNum)  // number → string

Reference#

• Variable declarations — Pine Script Official Docs
• Type system — Pine Script Official Docs