README.md

In dachosen1/DTwrappers: Wrapper for the data.table package

DTwrappers

Overview

Many newcomers to the data.table package are overwhelmed by the unique syntax . DTwrappers is useful in applying data.table with wrapper functions while still maintaining the data.table execution speed.

Install the current release from CRAN:

install.packages('DTwrappers')

Install the development version from GitHub:

devtools::install_github('dachosen1/DTwrappers')

Usage

DTwrappers package has 9 main functions. The main purpose of developing the package is to help users to apply data.table package faster and more convenient.

• create.filter.expression automatically creates filter expressions from a provided a character value, logical value, or expression stating the logical operations.

• dt.count is a wrapper to computations like dat[the.filter, .N, keyby = grouping.variables] that counts the number of rows that meets the qualification such as filter and the by (grouping variables).

• dt.filter subsets the data corresponding to the filtering statement.

• dt.select provides more flexibility in selecting the rows to include such as first.k, last.k, or specific row by setting up the parameters.

• df.define.variable is a wrapper to computations like dat[, new.variable := new.values] that allows users to re-define the variables so that users have freedom to set the variable name and the the values. The values could be either expression, direct code(data.table format), or character.

• dt.first.k.rows returns the first K number of rows from the given data frame based on the variables and the grouping varaibles statement.

• dt.last.k.rows returns the last K number of rows from the given data frame based on the variables and the grouping varaibles statement.

• dt.lapply is a wrapper to calculations like dat[the.filter, lapply(X = .SD, FUN = function.name), .SDcols = the.variables, keyby = grouping.variables] by specifying:

  • the.filter (character or expression) for the i step

  • the.variables (character vector of column names) for the .SDcols

  • the.functions (character vector of function names) for the functions to apply

  • grouping.variables (character vector of column names) for the variables to group by.

• dt.remove.variables is a wrapper to computations like dat[, this.variable := NULL] that removes selected columns from dat

dachosen1/DTwrappers documentation built on Dec. 25, 2019, 8:04 a.m.