extract_array_element: Extract Array Elements Safely

In Rduckhts: 'DuckDB' High Throughput Sequencing File Formats Reader Extension

Extract Array Elements Safely

Description

Helper function to safely extract elements from DuckDB arrays (returned as R lists) with proper error handling.

Usage

extract_array_element(array_col, index = NULL, default = NA)

Arguments

array_col	A list column from DuckDB array data
index	Numeric index (1-based). If NULL, returns full list
default	Default value if index is out of bounds

Value

The array element at the specified index, or full array if index is NULL

Examples

library(DBI)
library(duckdb)

con <- rduckhts_connect()
bcf_path <- system.file("extdata", "vcf_file.bcf", package = "Rduckhts")
rduckhts_bcf(con, "variants", bcf_path, overwrite = TRUE)
data <- dbGetQuery(con, "SELECT ALT FROM variants LIMIT 5")
first_alt <- extract_array_element(data$ALT, 1)
all_alts <- extract_array_element(data$ALT)
dbDisconnect(con, shutdown = TRUE)

Rduckhts documentation built on Oct. 25, 2026, 1:08 a.m.