pinescript: arrays

array 선언

<type>[] <identifier> = <expression>
var <type>[] <identifier> = <expression>
array<type> <identifier> = <expression>
var array<type> <identifier> = <expression>

array with 'var' keyword

//@version=5
indicator("Using `var`")
var a = array.new_float(0)
array.push(a, close)
if barstate.islast
    label.new(bar_index, 0, "Array size: " + str.tostring(array.size(a)) + "\nbar_index: " + str.tostring(bar_index), size = size.large)

'var' with constant array

var int[] lengths = array.from(2, 12, 20, 50, 100, 200)

using 'var' is more efficient as it avoids unnecessary computation but it still works.

//@version=5
indicator("Distance from high", "", true)
lookbackInput = input.int(100)
FILL_COLOR = color.green
// Declare array and set its values on the first bar only.
var fillColors = array.new_color(5)
if barstate.isfirst
    // Initialize the array elements with progressively lighter shades of the fill color.
    array.set(fillColors, 0, color.new(FILL_COLOR, 70))
    array.set(fillColors, 1, color.new(FILL_COLOR, 75))
    array.set(fillColors, 2, color.new(FILL_COLOR, 80))
    array.set(fillColors, 3, color.new(FILL_COLOR, 85))
    array.set(fillColors, 4, color.new(FILL_COLOR, 90))

// Find the offset to highest high. Change its sign because the function returns a negative value.
lastHiBar = - ta.highestbars(high, lookbackInput)
// Convert the offset to an array index, capping it to 4 to avoid a runtime error.
// The index used by `array.get()` will be the equivalent of `floor(fillNo)`.
fillNo = math.min(lastHiBar / (lookbackInput / 5), 4)
// Set background to a progressively lighter fill with increasing distance from location of highest high.
bgcolor(array.get(fillColors, fillNo))
// Plot key values to the Data Window for debugging.
plotchar(lastHiBar, "lastHiBar", "", location.top, size = size.tiny)
plotchar(fillNo, "fillNo", "", location.top, size = size.tiny)

array.set(id,index,value) : set a value at a specific index in an array

array.get(id,index): retrieve the value at a specific index

 

id: identifier of the array

index: position in the array

 

 

array를 0으로 declare하고 array.push()로 하나씩 집어넣기

// Declare array and set its values on the first bar only.
var fillColors = array.new_color(0)
if barstate.isfirst
    // Initialize the array elements with progressively lighter shades of the fill color.
    array.push(fillColors, color.new(FILL_COLOR, 70))
    array.push(fillColors, color.new(FILL_COLOR, 75))
    array.push(fillColors, color.new(FILL_COLOR, 80))
    array.push(fillColors, color.new(FILL_COLOR, 85))
    array.push(fillColors, color.new(FILL_COLOR, 90))

array.push(): adds a new element at the end of the array

 

array.from(): array선언할 때 모든 value를 알고 있다면 사용하기 좋음

//@version=5
indicator("Using `var`")
FILL_COLOR = color.green
var color[] fillColors =
  array.from(
   color.new(FILL_COLOR, 70),
   color.new(FILL_COLOR, 75),
   color.new(FILL_COLOR, 80),
   color.new(FILL_COLOR, 85),
   color.new(FILL_COLOR, 90))
// Cycle background through the array's colors.
bgcolor(array.get(fillColors, bar_index % array.size(fillColors)))