IsFirstDistinctMask / Boolean Layer

Create boolean mask columns marking the first occurrence of each distinct value. Similar to pandas duplicated(keep='first') negated. Returns True only for the first occurrence of each value based on row order.

Common applications:

Keeping first instance of duplicated records
Initial event detection
First occurrence analysis
Time series first appearance
Data deduplication

Example:

Index	Value	Is First Distinct
0	apple	true
1	banana	true
2	apple	false
3	orange	true
4	banana	false

Table

Mask

[, ...]

List of first distinct checking operations to perform. Each mask creates a new boolean column. Common scenarios:

Identifying first customer interactions
Finding initial system events
Marking first occurrences in logs
Tracking first entries in time series

At least one mask must be specified.

Select

column

The column to check for first distinct values. Works with any data type. The mask will be a boolean column where:

True indicates the first occurrence of each value
False indicates subsequent occurrences

Useful for identifying initial appearances and deduplication while preserving first instances.

AsColumn

name

Name for the new column. If not provided, the system generates a unique name. If AsColumn matches an existing column, the existing column is replaced. The name should follow valid column naming conventions.