str.*

Overview

The str namespace provides a set of string helpers. All functions are pure (no side effects) and available globally as str.*. Use them primarily for console.log formatting or building label text for Label entities.

Function reference

Function	Returns	Description
`str.format(template, ...args)`	`string`	Printf-style formatting
`str.length(s)`	`number`	Character count
`str.substring(s, start, len)`	`string`	Extract a portion
`str.contains(s, substring)`	`boolean`	Substring presence check
`str.split(s, sep)`	`string[]`	Split into array
`str.upper(s)`	`string`	Convert to upper case
`str.lower(s)`	`string`	Convert to lower case
`str.trim(s)`	`string`	Remove leading/trailing whitespace

`str.format` - placeholder syntax

str.format uses {} placeholders, filled left-to-right from the remaining arguments:

const msg = str.format("RSI: {} | EMA: {}", 72.4, 42300);
// "RSI: 72.4 | EMA: 42300"

const priceLabel = str.format("{} @ {}", ctx.instId, math.round(ctx.close(), 2));
// "BTC-USDT-SWAP @ 67832.14"

Practical example

const src = input.source("Source", "close");

onBar(() => {
  const rsi = ta.rsi(src, 14);
  if (na(rsi)) return;

  if (ctx.isLast()) {
    const label = str.format(
      "RSI({}) = {} | {}",
      14,
      math.round(rsi, 1),
      rsi > 70 ? "OB" : rsi < 30 ? "OS" : "Neutral"
    );
    console.log(label);
  }

  plot("RSI", rsi);
});

Splitting instrument IDs

// ctx.instId = "BTC-USDT-SWAP"
const parts = str.split(ctx.instId, "-");
const base  = parts[0]; // "BTC"
const quote = parts[1]; // "USDT"
const kind  = parts[2]; // "SWAP"

Case conversion

const upper = str.upper("hello"); // "HELLO"
const lower = str.lower("WORLD"); // "world"
const trimmed = str.trim("  foo  "); // "foo"

For the full list of available str.* functions, see the custom indicator spec. The table above covers the most commonly used subset.

math.*

Numeric utilities - use with str.format for formatted labels.

Label entity

Display formatted text on the chart canvas.

Getting Started

Core Concepts

Plotting

Drawing Entities

Technical Analysis

Utility Namespaces

Examples

Reference

Overview

Function reference

`str.format` - placeholder syntax

Practical example

Splitting instrument IDs

Case conversion

math.*

Label entity

​Overview

​Function reference

​str.format - placeholder syntax

​Practical example

​Splitting instrument IDs

​Case conversion

​Related pages

math.*

Label entity

Overview

Function reference

`str.format` - placeholder syntax

Practical example

Splitting instrument IDs

Case conversion

Related pages