TODO.md

In decisionpatterns/coercion: Utilities for Coercing (and Parsing) Values Between Types, Modes and Classes

TODO.md - coercion package TODO list

Multiple transformations attempts.

Provide a more robust infra-structure for transformation of values esp in a pipeline.

• [ ] tf_end should be changed to tf_commit or mutate_commit and have

• [ ] tf_try() should be able to selectively transform.

• [ ] tf_try() should not require . %>% ... syntax for transformations and adopt the magrittr syntax where the first argument is passed into the expression.

• [ ] tf_try() should track marginal and overall transformation success. It could even look at all possible orderings of the transformations (n!) for which is most efficient for a given input vector.

• [ ] tf_revert() in tf_try()

• We need to establish the difference if any between:

  • transformation,
  • map
  • lookup
  • mutate
  • coercion, etc. Reorganize/rename accordingly.

• [ ] tf_try should not introduce missing values.

• [ ] as_fct(), as_num(), as_int(), as_dt(), as_date(), as_time(), ...

• Maybe clear up type(of), mode, class

• [x] dry_run()

• [ ] Add unique= argument

• [x] Conditional Transformations tf_if : Only transform if there are no errors

• [ ] Rename tf_try() to tf_or() ?

• [ ] Factor tf_try()/tf_or() to separate package

• [ ] Allow tf_try to work on table in stead of vectors allowing for multiple parameters cf. dplyr::mutate_if()

• [ ] Support data.table

• [ ] tf_end should optionally produce a message about which values could not be transformed.

• [x] Add dry_run() that does nothing but report the changes. that dt[ , var := var %>% dry_run( ) ]

• [ ] Variant of dry_run that works like [ iris, Species := Species %>% dry_run() %>% .... ] or [ iris, Species := dry_run(.) %>% Species %>% %>% .... ]

• A method to fix the files

As.logic

Parse various values into a logical statement.

• as.logic()
• Add na parameter
• support regex for true, false, na

• as_logic

• Create other classes that mask logical with other vales Yes/No

General parsers

Parsers: p_

• [x] p_age : parses an age/duration suffixed with [YyMmWwDd] and express the age in years.

• [ ] Consider factoring out p_ functions as part of a mutators, transformers or parsers package.

• [-] can_be_all -- see which_can_be

• p_excel_dt needs to cascade through options perhaps using anytime package.

• can need to be refactor to think how it would work with
• recursive objects
• objects with length

• possible package name: anyany`

• [ ] logical variant of which_can_be and which_cant_be

• [ ] strict argument of which_can_be and which_cant_be

• coerce(x, ..., env) ... : list of functions or expressions to try in order element-wise; first function that produces a non-NA value gets priority env : environment/data.frame to evaluate ... in cf. p_excel_dt

x %>% coerce( mdy_hms, mdy_hm, mdy )

x %>% ifelse(is.na(y),y,z)

• [-] cast as an alias for coerce? No. Why so complicated?

• repalce p_ -> as_ prefixes.

• This allows as_logic to become as_logical

• What is the relationship to setAs?

decisionpatterns/coercion documentation built on Nov. 4, 2019, 10:23 a.m.