# Item recommendation filter expression examples
<a name="item-recommendation-filter-examples"></a>

The following filter expressions show how to filter item recommendations based on item interactions, item metadata, and user metadata. They are organized by data type.

**Topics**
+ [Item interaction data](#item-interaction-filter-examples)
+ [Item data](#item-filter-examples)
+ [User data](#user-filter-examples)

## Item interaction data
<a name="item-interaction-filter-examples"></a>

The following expression excludes items based on an event type (such as click) or event types that you specify when you get recommendations using the `$EVENT_TYPE` parameter.

```
EXCLUDE ItemID WHERE Interactions.EVENT_TYPE IN ($EVENT_TYPE)
```

 The following expression excludes items that a user clicked or streamed.

```
EXCLUDE ItemID WHERE Interactions.EVENT_TYPE IN ("click", "stream")
```

The following expression includes only items that the user has clicked.

```
INCLUDE ItemID WHERE Interactions.EVENT_TYPE IN ("click")
```

## Item data
<a name="item-filter-examples"></a>

The following expression excludes items based on a category or categories that you specify when you get recommendations using the `$CATEGORY` parameter.

```
EXCLUDE ItemID WHERE Items.CATEGORY IN ($CATEGORY)
```

The following expression includes only items that are cheaper than the current item (the item you specify in the request for related items recommendations), and created by the same studio as the current item. You can apply a filter with the CurrentItem element only if your domain use case or custom recipe generates related items recommendations.

```
INCLUDE ItemID WHERE Items.PRICE < CurrentItem.PRICE AND Items.GENRE IN CurrentItem.GENRE
```

 The following expression excludes items based on multiple levels of categorical fields. It excludes items with a CATEGORY\_L1 value of `shoe` that *do not* have a CATEGORY\_L2 value of `boot`. 

```
EXCLUDE ItemID WHERE Items.CATEGORY_L1 IN ("shoe") AND Items.CATEGORY_L2 NOT IN ("boot")
```

The following expression includes only items with a price less than or equal to the price that you specify when you get recommendations using the `$PRICE` parameter.

```
INCLUDE ItemID WHERE Items.PRICE <= $PRICE
```

The following expression includes only items that have been created earlier than a timestamp (in Unix epoch time) that you specify when you get recommendations.

```
INCLUDE ItemID WHERE Items.CREATION_TIMESTAMP < $DATE
```

The following expression includes only items with a genre or genres that you specify when you get recommendations using the `$GENRE` parameter.

```
INCLUDE ItemID WHERE Items.GENRE IN ($GENRE)
```

The following expression includes only items that are more expensive than the current item *and* created more recently than a timestamp (in Unix epoch time) that you specify. You might use this filter if you are getting related item recommendations, and want to apply some specific business rules based on price and a varying creation date.

```
INCLUDE ItemID WHERE Items.PRICE < CurrentItem.PRICE AND Items.CREATION_TIMESTAMP > $DATE
```

## User data
<a name="user-filter-examples"></a>

The following expression excludes items with a genre or genres that you specify when you get recommendations using the `$GENRE` parameter, but only if the current user's age is equal to the value that you specify when you get recommendations using the `$AGE` parameter. 

```
EXCLUDE ItemID WHERE Items.GENRE IN ($GENRE) IF CurrentUser.AGE = $AGE
```

The following expression includes only items with `watch` for CATEGORY\_L1 and `luxury` for CATEGORY\_L2, if the current user's age is over `18`.

```
INCLUDE ItemID WHERE Items.CATEGORY_L1 IN ("watch") AND Items.CATEGORY_L2 IN ("luxury") IF CurrentUser.AGE > 18
```