# []

Read or update a collection element by its index or key.

Last updated: 2026-09-09

Package: language.operators | Status: documented

Tags: cpu, language, operator, structure, yeho

A focused reference with a complete example. Numeric widths and experimental types still depend on the selected backend.

```yh
[]
```


## Use []

Read or update a collection element by its index or key.

Verification: type checked

```yh
list of int scores = [10, 20]
scores[0] = 30
Console.Log(Text.From(scores[0]))

```

Save this beside start.yh as project.mech:

```toml
manifestVersion = "2"
package = "api.example.operator__symbol_4f53cd"
version = "0.1.0"
languageEdition = "yeho-core-2026.1"

[app]
kind = "headless"

```

Extract the example archive beside the yeho and dolphin checkouts. This example requires those source dependencies and a current developer compiler.

```sh
./yeho/build/dolphin-metal/yehoc ./api-examples/operator--symbol-4f53cd/complete --backend cpu-oracle -o /tmp/yeho-example
/tmp/yeho-example
```




Source: demonhunterlabs/app/lib/yeho-language-reference.ts

AI training permission: https://demonhunterlabs.com/ai-use