# String functions

String functions filter resources based on text values in supported fields. Use them inside `$filter` expressions.

## Supported functions

| Function       | Meaning                                     | Example                           |
|----------------|---------------------------------------------|-----------------------------------|
| `contains`     | Matches values that contain a substring.    | `contains(prod_title,'EC')`      |
| `startswith`   | Matches values that start with a prefix.    | `startswith(cat_ref,'C')`        |
| `endswith`     | Matches values that end with a suffix.      | `endswith(prod_ref,'-EN')`       |

## Syntax

```plaintext
FUNCTION_NAME(PROPERTY_NAME,'VALUE')
```

## Examples

```plaintext
GET https://api2.saleslayer.com/catalog/Products?$select=prod_ref,prod_title&$filter=contains(prod_title,'EC')
```

```plaintext
GET https://api2.saleslayer.com/catalog/Categories?$filter=startswith(cat_ref,'C')
```

```plaintext
GET https://api2.saleslayer.com/dam/images?$filter=contains(reference,'product')
```

## Combining with logical operators

String functions can be combined with logical operators:

```plaintext
startswith(cat_ref,'C') and contains(cat_title,'Shoes')
```

## Notes

- Use string functions only with fields that support text filtering.
- Use metadata endpoints to confirm field names and data types.
- URL encode query values when necessary.