README.md

In ctbrown/magrittr.plus: Drop-In, Opinionated ("Data First, Context Next") 'magrittr' Replacement with both get/set accessors.

magrittr.plus

Drop-In, Opinionated ("Data First, Context Next") 'magrittr' Replacement with both get/set accessors.

This packages provides a monkey patch for 'magrittr' so that elements/attributes of recursive objects (e.g. lists, data.frames, S3, S4, R6, env, etc,) can be accessed using only the pipe '%>%' operator and their names. That is, 'magrittr.plus' looks for the RHS of the pipe within the LHS before looking in the enclosing scope. This enhancement eliminates the need for .$ or extract[2] and is more in keeping with the tidyverse that favors "Data First, Context Next" evaluation. Additionally, it promotes more concise and legible code. Additionally, replacement methods also allows for inline replacement of a recursive objects elements/attributes: 'LHS %>% RHS <- newvalue'

Install

CRAN

install.packages('magrittr.plus")

github.com

install_github("decisionpatterns/magrittr.plus")

Benefits

• Tidyverse Opinionated ("Data First, Context Next")
• Simple, more legible syntax
• DWIM: Behaves more like . method of other languages
• No need for 'extract2' method
• Avoids ugly:
• obj %>% .$name
• Works with all recursive (non-atomic) objects: S3, S4, R6 and proto objects
• Supports nested objects, e.g. list of lists
• Supports replacement: LHS %>% RHS <- newvalue

Usage

library(magrittr.plus)    # Use instead of magrittr

ll <- list( a=1, b=2 )

# Accesor
ll %>% a         # 1

# Replacement
ll %>% a <- 2  
ll %>% a         # 2

TLDR;

magrittr.plus promotes tidy-compliant, cleaner more legibly code eliminating the need for the extract2 function or the ugly obj %>% .$name syntax. Consider, the common case of extracting a value from a list or data.frame by name. The way magrittr allows this is:

ll <- list( a=1:10, b=rnorm(10) ) 
ll %>% extract2('a')  # OR
ll %>% .$a

magrittr.plus allows you to express this as:

ll %>%  a

There are two good reasons for promoting this syntax. First, it makes %>% behave more like the . operator in other languages. In Python, JAVA, etc. The . is a dereferncing operator that looks inside the object first. This same useful semantic is promoted by magrittr.plus.

Second, magrittr.plus favors the more common case. Especially when working interactively, the coder is interested in inspecting a recursive object. (This is one feature that has made data.table a success.) magrittr.plus follows the "Data First, Context Next" paradigm, but does not prevent the use of extract2 or .$name syntax. They work to promote backward compatibility.

magrittr.plus also provides a natural replacement function. This allows syntax such as the following to do the right thing.

ll %>% a
ll %>% a <- 5:10
ll %>% a         # 5:10

The equivalent cannot be done with either extract2 or .$name and instead requires the inset2 function for extra cognitive bloat.

ctbrown/magrittr.plus documentation built on May 23, 2020, 12:17 p.m.