Pulse Documentation

name: op-filter-expression
description: Keep records for which an expr-lang expression evaluates truthy against record fields.
kind: operator
category: FILTER
operator: FILTER_EXPRESSION
type: reference
applies_to: process, compose, predict
examples_tags: [cohort-analysis, feature-engineering, streaming-friendly]

Use when

Keeps the rows for which a written yes-or-no condition is true, for rules the other filters cannot state, such as two fields together.

Questions it answers:

• Which customers spent over 500 and joined this year?
• Which records have an end date before their start date?

Use something else:

• FILTER_INCLUDE when you only need to keep a list of values.
• FILTER_RANGE when you only need a low and a high limit.

Params

Inputs

Categorical → STRING; set_* → []string (has_any(tags, "a")); decimal128 → Decimal128.

Output

Row-level predicate. No emitted column.

Components

Floor only: universal {n_in, n_out, n_null_input} (response-components). n_null_input stays 0 — no fixed input field. Mergeable.

Gotchas

• Compiled once; bad syntax / types → PROCESSING_RUNTIME at build.
• Null binds nil: == false, != true, x ?? 0 fills; > / + / len on nil → predicate UNKNOWN, row dropped.
• Error / non-bool on a non-null row → PROCESSING_RUNTIME.
• % on a field: float math.Mod (age % 2 == 0, dividend’s sign); % 0 → NaN, as / 0 → ±Inf.
• No attribute output — filters run first.

See

• pulse_examples_search tags=[feature-engineering]
• Skills: expression-language (maths / vector functions, ExprFunctions, LookupTables), aggregation-design, response-components