export_nest: Export Nested Data with Advanced Grouping and Flexible...

In mintyr: Streamlined Data Processing Tools for Genomic Selection

Export Nested Data with Advanced Grouping and Flexible Handling

Description

The export_list function exports nested data from a data.frame or data.table with sophisticated grouping capabilities, supporting multiple nested column types and flexible file export options.

Usage

export_nest(
  nest_dt,
  group_cols = NULL,
  nest_col = NULL,
  export_path = tempdir(),
  file_type = "txt"
)

Arguments

nest_dt	A data.frame or data.table containing nested columns of data.frames, data.tables, or lists to be exported.
group_cols	Optional character vector specifying grouping columns. If NULL, uses all non-nested columns as grouping variables.
nest_col	Optional character string indicating the nested column to export. If NULL, automatically selects the first nested column.
export_path	Base directory path for file export. Defaults to a temporary directory created by tempdir().
file_type	File export format, either "txt" (tab-separated) or "csv". Defaults to "txt".

Details

Comprehensive Nested Data Export Features:

• Automatic detection and handling of different nested column types

• Flexible grouping strategies with intelligent column selection

• Hierarchical directory structure generation based on grouping columns

• Support for mixed nested column types (data.frame, data.table, list)

• Multi-threaded file writing for enhanced performance

• Informative messaging and warning system

Nested Column Detection Hierarchy:

1. Prioritizes data.frame/data.table nested columns

2. Falls back to regular list columns if no data.frame columns exist

Grouping Column Selection Strategy:

1. When group_cols is NULL, uses all non-nested columns

2. Provides warnings about unused non-nested columns

3. Validates provided group columns

File Export Characteristics:

• Supports "txt" (tab-separated) and "csv" formats

• Uses multi-threading via parallel::detectCores()

• Creates nested directory structure based on grouping variables

Value

An integer representing the total number of files exported successfully.

Note

Key Capabilities:

• Handles complex nested data structures

• Performs type conversion for nested content

• Utilizes multi-threaded file export for optimal performance

• Provides comprehensive column selection feedback

Examples

# Example 1: Basic nested data export workflow
# Step 1: Create nested data structure
dt_nest <- w2l_nest(
  data = iris,              # Input iris dataset
  cols2l = 1:2,             # Columns to be nested
  by = "Species"            # Grouping variable
)

# Step 2: Export nested data to files
export_nest(
  nest_dt = dt_nest,        # Input nested data.table
  nest_col = "data",        # Column containing nested data
  group_cols = c("name", "Species")  # Columns to create directory structure
)
# Returns the number of files created
# Creates directory structure: tempdir()/name/Species/data.txt

# Check exported files
list.files(
  path = tempdir(),         # Default export directory
  pattern = "txt",          # File type pattern to search
  recursive = TRUE          # Search in subdirectories
)
# Returns list of created files and their paths

# Clean up exported files
files <- list.files(
  path = tempdir(),         # Default export directory
  pattern = "txt",          # File type pattern to search
  recursive = TRUE,         # Search in subdirectories
  full.names = TRUE         # Return full file paths
)
file.remove(files)          # Remove all exported files

mintyr documentation built on April 4, 2025, 2:56 a.m.