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Filtering
When recommending items to a user, LYNX's AI prediction engine selects the most relevant ones to the user. However, it may be your policy to not recommend certain items. To narrow down the scope of the recommendable items, you can use the
filter parameter when invoking the recommendation API methods.A
filter is an expression that allows you to filter the recommended items based on the values of their attributes. The attributes on which you can filter are the fields in your catalog. A filter expression defines the condition to be met for the items to be returned, and it's a combination of one or more predicates tied together by logical operators (AND, OR, and NOT). A predicate is an expression that returns TRUE or FALSE.A predicate has the following form:
p: [attribute] [comparison operator] [value][attribute] | [comparison operator] | [value] |
The name of a field in your catalog. | Can be a string, a number, or a boolean value. String values must be enclosed in single quotes (e.g. 'string_value'). |
p1:
Price > 15p2:
Category = 'Clothing'p3:
InStock = 'Yes'Since a filter expression is a combination of one or more predicates tied together by logical operators, the following are valid filtering expressions:
Price > 15 (p1)Price > 15 AND Category = 'Clothing' (p1 AND p2)Price > 15 AND Category = 'Clothing' AND InStock = 'Yes' (p1 AND p2 AND p3)The order of precedence for the logical operators is NOT (highest), followed by AND, followed by OR. You can use parentheses to override this precedence in a filter expression.
(Price > 15 OR Category = 'Clothing) AND InStock = 'Yes' ((p1 OR p2) AND p3)Consider the following sample catalog:
Id | Title | Category | Price | InStock | SpecialOffer |
1234 | Black Check Knit Skirt | Clothing | 19.00 | Yes | Yes |
3738 | Gold Midi Pencil Skirt | Clothing | 34.90 | Yes | No |
9737 | Black Leather Women Bag | Accessories | 24.90 | No | Yes |
1002 | White Chain Zip Belt Bag | Accessories | 14.90 | Yes | No |
6343 | Leather-Look Leggings | Clothing | 13.90 | No | No |
... | ... | ... | ... | .. | |
Suppose USER_A has purchased ITEM_123. You may want to recommend to USER_A other items that are frequently bought together with ITEM_123. However, it may be your policy to recommend only items that are in stock. To do so, you should use the following simple filtering expression:
InStock='Yes'The resulting API call should look like this:
https://ai.kickdynamic.cloud/api/v1/recommender/YOUR_MERCHANT_ID/items/ITEM_123
/bought-together?userId=USER_A&topK=10
&attributes=Title,Category,Price
&filter=InStock='Yes'
Suppose USER_A has purchased ITEM_123. You may want to recommend to USER_A other items that are frequently bought together with ITEM_123. You may want to recommend only items that are in stock, that belong to the Clothing category, and that are on special offer. To do so, you should use the following filtering expression:
(InStock='Yes' AND Category='Clothing' AND SpecialOffer='Yes') The resulting API call should look like this:
https://ai.kickdynamic.cloud/api/v1/recommender/YOUR_MERCHANT_ID/items/ITEM_123
/bought-together?userId=USER_A&topK=10
&attributes=Title,Category,Price
&filter=(InStock='Yes' AND Category='Clothing' AND Promotion='Yes')
Suppose you want to recommend the most popular items in a specific category, but you also want the recommended items to have a price of at least 15.00 £ (in other words, you want the price to be equal to or greater than 15.00 £). To achieve your goal, you can use the following filtering expression:
(Price >= 15.00)The resulting API call should look like this:
https://ai.kickdynamic.cloud/api/v1/recommender/YOUR_MERCHANT_ID/items/top-in-category
&attributes=Title,Category,Price
&filter=(Price >= 15.00)
Operator | Meaning |
= | Equal to |
> | Greater than |
< | Less than |
>= | Greater than or equal to |
<= | Less than or equal to |
<> | Not equal to |
LIKE | Matches a specified pattern. |
The LIKE operator determines whether a text field in the catalog matches a specified pattern. A pattern can include regular characters and wildcard characters. Regular characters must match exactly the characters in the specified field, while wildcard characters can match arbitrary fragments of the specified field.
field [ NOT ] LIKE patternfieldis any valid text field in the catalog.pattern is the specific string of characters to search for infield and can include the following wildcard character.Wildcard character | Description | Example |
% | Any string of zero or more characters. | description LIKE '%dress%' finds all items with the word 'dress' anywhere in the item's description. |
When you do string comparisons using the LIKE operator, all characters in the pattern string are significant, including any leading or trailing spaces.
Logical operators are used to combine predicates to build more complex filtering expressions.
Operator | Meaning |
AND | TRUE if all evaluated expressions are TRUE |
OR | TRUE if any of the evaluated expressions is TRUE |
NOT | Reverses the value of any other operator |
Operator | Meaning |
+ | Add |
- | Subtract |
* | Multiply |
/ | Divide |
% | Modulus |