# ＊ NewNumberMapper

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**＊SDV Enterprise Feature.** This feature is available to our licensed users and is not currently in our public library. For more information, visit our page to [Explore SDV](https://docs.sdv.dev/sdv/explore/sdv-enterprise/compare-features).
{% endhint %}

The `NewNumberMapper` creates and applies a consistent mapping between real numbers and fake, synthetic numbers. The mapping preserves the geographical context of the phone numbers. That is, numbers belonging to a region are mapped to fake phone numbers in the same region.

```python
from rdt.transformers.phone_number import NewNumberMapper

mapper = NewNumberMappper()
```

## Parameters

**`default_country`**: If phone number does not have an international country code, provide the country code to use.

<table data-header-hidden><thead><tr><th width="215"></th><th></th></tr></thead><tbody><tr><td>(default) <code>None</code></td><td>No default country. All phone numbers must have international country codes.</td></tr><tr><td><code>&#x3C;string></code></td><td>A string representing an <a href="https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2">Alpha-2 country code</a> (<code>"US"</code>)</td></tr></tbody></table>

### Examples

```python
from rdt.transformers.phone_number import NewNumberMapper
mapper = NewNumberMappper(default_country='US')
```

## Attributes

After fitting the transformer, you can access the learned values through the attributes.

**`mapping`**: A dictionary that maps the original, real phone number to a new, fake phone number

```python
>>> transformer.mapping
{
  '(617)253-3400': '(617)100-1234',
  '(617)253-2142': '(617)555-2223',
  ...
}
```