Incremental Counter within DataFrame only When a Condition is Met in R Using cumsum() with factor() and as.integer().

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Understanding Relational Count Exclusion Using data.table: A Practical Guide to Advanced Joining Techniques

Joining Data Tables Based on Column Conditions: A Comprehensive Guide

What is the equivalent of `dplyr::mutate` in data.table, R?

Creating Deciles with Equal Total Revenue: A Step-by-Step Approach Using R

Creating a Counter Variable in R Grouped by ID that Conditionally Resets

How to Create a Counter Column in R's Data.table Package Using Cumulative Sums

Filling Missing Values by Group in R's data.table: A Native Solution Approach

Optimizing Multivariate Row Subsetting of Data.tables Using Vectors and setkeyv() Function