# var

## Overview

The `var` statement is used to create or update a variable.

{% hint style="success" %}
A number of variables are automatically created before the commencement of a Transcript task. Please refer to the **Variables** section in the [Introduction](https://olddocs.exivity.io/3.4.3/data-pipelines/transform) to this guide for further details.
{% endhint %}

## Syntax

**`var`***`name`***`=`***`value`*

{% hint style="danger" %}
As the value may be derived from an expression (see *Using an expression to set a variable* below) it is recommended that variable values be quoted in order to avoid characters such as `/` being interpreted as mathematical operators.
{% endhint %}

## Details

A variable is a named value. Once defined, the name can be used in place of the value for the rest of the transcript task. This can be useful in that it permits configuration of various parameters at the top of a transcript task, which makes maintenance easier.

Both the *name* and the *value* parameters must be present, and there must be a space on each side of the **`=`** character. To use a space or tab in a variable value, use an escape or double quote the value:

```
var example = "Hello world"
var example = Hello\ world
```

A variables is referenced by enclosing its name with `${` and `}`. For example a variable called `outputFile` can be referenced using `${outputFile}`.

{% hint style="warning" %}
Variable names are case sensitive, therefore `${variableName}` and `${VariableName}` are separate variables.
{% endhint %}

If there is already a variable called *name* then the `var` statement will update the value.

{% hint style="warning" %}
The value of a variable may not exceed 1023 characters
{% endhint %}

### Using an expression to set a variable

As well as a literal value, an expression may be specified, in which case the variable is set to the output of that expression. For example:

```
var value1 = 5
var value2 = 10
var largest = @MAX(${value1}, ${value2})
```

For a full list of available functions please refer to the [functions ](https://olddocs.exivity.io/3.4.3/data-pipelines/transform/if#functions)section of the documentation for the [if](https://olddocs.exivity.io/3.4.3/data-pipelines/transform/language/if) statement.

## Example

```
# ----> Start Config <----
var tmp_folder = AzureTmp
# ----> End Config <----

import "system/extracted/${tmp_folder}/${dataDate}.csv" source Azure alias usage
import "system/extracted/${tmp_folder}/rates.csv" source source Azure alias rates
```