mintyr (version 0.1.0)

w2l_split: Reshape Wide Data to Long Format and Split into List

Description

The w2l_split function reshapes wide-format data into long-format and splits it into a list by variable names and optional grouping columns. It handles both data.frame and data.table objects.

Usage

w2l_split(data, cols2l = NULL, by = NULL, split_type = "dt", sep = "_")

Value

A list of data.table or data.frame objects (depending on split_type), split by variable names and optional grouping columns.

• If by is NULL, returns a list split by variable names only.

• If by is specified, returns a list split by both variable names and grouping variables.

Arguments

data

data.frame or data.table

• Input dataset in wide format

• Automatically converted to data.table if necessary

cols2l

numeric or character columns to transform

• Specifies columns for wide-to-long conversion

• Can be column indices or column names

• Default is NULL

by

numeric or character grouping variables

• Optional columns for data splitting

• Can be column indices or column names

• Used to create hierarchical split structure

• Default is NULL

split_type

character output data type

• Defines split data object type

• Possible values:

  • "dt": split data.table objects

  • "df": split data.frame objects

• Default is "dt"

sep

character separator

• Used for combining split names

• Default is "_"

Details

The function melts the specified wide columns into long format and splits the resulting data into a list based on the variable names and any additional grouping variables specified in by. The split data can be in the form of data.table or data.frame objects, controlled by the split_type parameter.

Both cols2l and by parameters accept either column indices or column names, providing flexible ways to specify the columns for transformation and splitting.

See Also

Related functions and packages:

• tidytable::group_split() Split data frame by groups

Examples

# Example: Wide to long format splitting demonstrations

# Example 1: Basic splitting by Species
w2l_split(
  data = iris,                    # Input dataset
  by = "Species"                  # Split by Species column
) |> 
  lapply(head)                    # Show first 6 rows of each split

# Example 2: Split specific columns using numeric indices
w2l_split(
  data = iris,                    # Input dataset
  cols2l = 1:3,                   # Select first 3 columns to split
  by = 5                          # Split by column index 5 (Species)
) |> 
  lapply(head)                    # Show first 6 rows of each split

# Example 3: Split specific columns using column names
list_res <- w2l_split(
  data = iris,                    # Input dataset
  cols2l = c("Sepal.Length",      # Select columns by name
             "Sepal.Width"),
  by = "Species"                  # Split by Species column
)
lapply(list_res, head)            # Show first 6 rows of each split
# Returns similar structure to Example 2