The ML.HASH_BUCKETIZE function

This document describes theML.HASH_BUCKETIZE function, which lets youconvert a string expression to a deterministic hash and then bucketize it by themodulo value of that hash.

You can use this function with models that supportmanual feature preprocessing. For moreinformation, see the following documents:

• End-to-end user journeys for ML models
• Contribution analysis user journey

Syntax

ML.HASH_BUCKETIZE(string_expression, hash_bucket_size)

Arguments

ML.HASH_BUCKETIZE takes the following arguments:

• string_expression: theSTRING expression to bucketize.
• hash_bucket_size: anINT64 value that specifies the number of buckets tocreate. This value must be greater than or equal to0. Ifhash_bucket_size equals0, the function only hashes the string withoutbucketizing the hashed value.

Output

ML.HASH_BUCKETIZE returns anINT64 value that identifies the bucket.

Example

The following example bucketizes string expressions into three buckets:

SELECTf,ML.HASH_BUCKETIZE(f,3)ASbucketFROMUNNEST(['a','b','c','d'])ASf;

The output looks similar to the following:

+---+--------+| f | bucket |+---+--------+| a |   0    |+---+--------+| b |   1    |+---+--------+| c |   1    |+---+--------+| d |   2    |+------------+

What's next

• For information about feature preprocessing, seeFeature preprocessing overview.