# op_index · Rell standard library · Chromia Docs (concept)

> val op_index: integer The index of the current operation within the transaction. The first operation in the transaction has index 0 . Throws exception — if

Source: https://docs.chromia.com/pages/rell-stdlib/-rell-system-library/op_context/op_index/

PROPERTY

# op\_index

```signature
val op_index: integer
```

The index of the current operation within the transaction.

The first operation in the transaction has index `0`.

**Throws**

* `exception` — if there is no operation context

Since 0.10.4

[View this page on docs.chromia.com](https://docs.chromia.com/pages/rell-stdlib/-rell%20-system%20-library/op_context/op_index.html)Generated API reference, mirrored from the live docs