---
title: "lastIndexOf"
description: "Searches for the last occurrence of the substring inside of string."
---

# lastIndexOf

> Searches for the last occurrence of the substring inside of string.

**This function is used by Ignition's Expression language.**

## Description

Searches for the last occurrence of the substring inside of string. Returns the index of where substring was found, or -1 if it wasn't found. The first position in the string is position 0.

## Syntax

`lastIndexOf(string, substring)`

### Parameters

| Type             | Parameter   | Description                                                                                      |
|------------------|-------------|--------------------------------------------------------------------------------------------------|
| String or List   | `string`    | The string to search through. As of version 8.1.8, this parameter also accepts tuples and lists. |
| String           | `substring` | The string to search for.                                                                       |

### Returns

**Integer** - The index where the substring was last found in the string. Returns -1 if the substring is not found.

## Examples

```py title="Code Snippet"
lastIndexOf("Hamburger", "urge") //Returns 4.
```

```py title="Code Snippet"
lastIndexOf("Test", "") //Returns 4.
```

```py title="Code Snippet"
lastIndexOf("Dysfunctional", "fun") //Returns 3.
```

```py title="Code Snippet"
lastIndexOf("Dysfunctional", "marble") //Returns -1.
```

```py title="Code Snippet"
lastIndexOf("banana", "n") //Returns 4.
```