Out of the list of attributes sourced from the feed, you select one, like in the example: "`brand` equals `acme`"
#### Context value
The filters of any recommendation type can use the attributes of the item that the customer is currently browsing. For example, you can create a filter that shows items with the same category as the viewed item:
It allows you to use the customer attribute as the value of the item attribute. For example, you can filter displayed items by size, using the size value stored in an attribute of a customer who displays the recommendation.
#### Array
This value type is only available for the **In** operator.
It lets you include items whose attribute matches a value from an array.
You can use it with attributes whose values are strings, numbers, and arrays. If you compare an array to an array, at least one value between them must be the same.
To define an array:
1. Click **0 items**.
**Result**: A pop-up appears.
2. In the text box, you can paste the array from a notepad, enter values manually or you can select values from the dropdown list.
3. Confirm your choice by clicking **Add**.
Allows you to select an aggregate as a value of the attribute from the item catalog.
- The **aggregate result must match the item attribute** type defined in the feed. For example, if the attribute of an item is a number (price), you must select an aggregate that produces a number as the result.
- You can use **two various aggregates** or **expressions**, or **one expression** and **one aggregate**. This **limit** applies per **one recommendation campaign** for filtering and boosting options. Multiple occurrences of the same aggregate count as one towards the limit.
- If the condition contains an aggregate whose result is **null**, this condition is **skipped**. If it's the only condition, the result is that no filter is applied (all items match).
- Using `null` as a **condition** in an aggregate is **impossible**. Using a `null` value as a string is not supported.
#### Expression
Allows you to select an expression as a value of the attribute from the item catalog.
- The **expression result must match the item attribute** type defined in the feed. For example, if the expression of an item is a text string (favorite color of the customer), you must select the expression that produces a result which is a text string as well.
- You can use **two various expressions** or **aggregates**, or **one expression** and **one aggregate**. This **limit** applies to **one recommendation campaign** for filtering and boosting options. Multiple occurrences the same expression count as one towards the limit.
- If the condition contains an expression whose **result** is **null**, this condition is **skipped**, unless it's the only condition.
- Using `null` as a **condition** in an expression is **impossible**. Using a `null` value as a string is not supported.
#### Formula
You can create it through the [IQL Query builder](/docs/ai-hub/recommendations-v2/recommendation-filters#iql-query). It allows you to define the advanced conditions, which can be done with the available operators and its value types. For example, if you want to display in the recommendation frame items which are discounted more than the currently viewed item.
| Function | Description | Syntax & Example of use |
|---|---|---|
| ADD | Adds a constant to value of a selected variable | 1. Syntax   |
| AVG | Returns the average value of a selected attribute (for example, a shoe size) | 1. Syntax   |
| BOTTOM_K | Returns the bottom K number of items from a list generated based on a specified item attribute, which may be expressed as a range such as price, number of visits to the item's page, or the quantity of item purchases. The final component of the function syntax allows for defining filter conditions to narrow down the results of the function; if you don't want to apply filters, select the Take All option - this component cannot be empty. | 1. Syntax   clicmo brand in the last 7 days |
| CATEGORY | Allows to define the categories to be included or excluded while filtering items | 1. Syntax    Electronics > Phones and Smartphones > Smartphones, or in one of the subcategories of Electronics > Phones and Smartphones > Smartphones are included in the result. The filter also includes items that have the category defined in the additionalCategories parameter. The number allows to manipulate the category value. A positive number defines how many subcategories from the right should be dropped. If in the second example 0 was replaced with 1, these would be the categories included in the filter: Electronics > Phones and Smartphones. A negative number defines how many subcategories from the left should be included. If in the second example 0 was replaced with -1, Electronics would be included in the filter. |
| IF | Allows logical comparisons between values and defining actions to be performed when the condition is met or not. | 1. Syntax   |
| MULTIPLY | Multiplies the value of a variable by a specified constant | 1. Syntax   0.8. |
| MIN | This function returns the lowest value in a set of values | 1. Syntax   |
| MAX | This function returns the highest value in a set of values. | 1. Syntax   |
| NOT | Negates a filter | 1. Syntax   |
| TOP_K | Returns the top K number of items from a list generated based on a specified item attribute, which may be expressed as a range such as price, number of visits to the item's page, or the quantity of item purchases. The final component of the function syntax allows for defining filter conditions to narrow down the results of the function; if you don't want to apply filters, select the Take All option - this component cannot be empty. | 1. Syntax   |
| | | 
