Conditionals & Loops — kScript

Conditionals and loops control which code runs during each bar's calculation phase. Use them for decision-making logic, counted iteration, and conditional searches while keeping the per-bar execution model in mind.

Overview

Control Type	Description	Features
Conditional Statements	Use `if/else` statements to execute different code paths based on conditions. Essential for decision-making logic in your indicators.	Condition-based execution, multiple branches, boolean logic
For Loops	Use `for` loops when you know the number of iterations in advance. Perfect for counted iterations and array-like processing.	Known iteration count, counter-based control, array-like processing
While Loops	Use `while` loops when the number of iterations depends on a condition. Ideal for search patterns and conditional iteration.	Condition-based control, dynamic iteration count, search patterns

Construct	Description
`if/else`	Conditional execution statements
`for`	Counted iteration loop
`while`	Conditional iteration loop

if/else - conditional execution statements

if (condition) { /* body */ } else { /* alternative */ }

Parameter	Type	Description
`condition`	boolean expression	Expression that evaluates to true or false
`if body`	code block	Code executed when condition is true
`else body`	code block	Code executed when condition is false (optional)

Returns: void (executes conditional code).

// Basic if/else with price direction
var direction = "neutral"
if (closeTs[0] > closeTs[1]) {
  direction = "up"
} else {
  direction = "down"
}

for - counted iteration loop

for (var i = start; i < end; i = i + increment) { /* body */ }

Parameter	Type	Description
`initialization`	var declaration	Initialize the loop counter variable
`condition`	boolean expression	Loop continues while this condition is true
`increment`	assignment	Update the counter variable each iteration

Returns: void (executes loop body).

// Basic iteration
for (var i = 1; i <= 10; i = i + 1) {
    print("i = ", i)
}

while - conditional iteration loop

while (condition) { /* body */ }

Parameter	Type	Description
`condition`	boolean expression	Loop continues while this condition is true

Returns: void (executes loop body).

// While (use sparingly due to execution limits)
var j = 0
while (j < 3) {
  print("j = ", j)
  j = j + 1
}

Tips

Infinite Loop Protection

Always ensure loop conditions will eventually become false. Infinite loops will cause your script to hang and may be terminated by the runtime.

Variable Scope

Loop variables like i are scoped to the loop. Use var declarations inside loops for temporary calculations.

Performance

Loops run during the calculation phase of each bar. Keep iterations reasonable to maintain good performance across large datasets.

Timeseries Restriction

You cannot declare timeseries inside loops. Timeseries must be declared in global scope only.