Parsing custom Dates and Months in Roman Numerals with Tidyverse?

Question

Tidyverse has the fabulous Readr and it has a wide variety of parse commands, such as parse_date, parse_*, parse_factor and guess_parser. I have a custom month-year format like the below in terms of Roman numerals such that

> emptyOffices$Month
[1] " II/90" " I/91"  " II/91" " I/92"  " II/92" " I/93"  " II/93"

> guess_parser(emptyOffices$Month)
[1] "character"

where I stands for January, II stands for February and so no. For example, II/90 stands for February 1990. The guess_parser guess the meaning of the month-year wrong. Perhaps, there is a tool by which I can define months to help the parser to understand this?

Does there exist some tool in some Tidyverse package to read custom dates like with Roman numerals?

pogibas · Accepted Answer · 2017-09-13T12:36:15.577

There must be better tidy solution, but this one works:

library(dplyr)
foo <- c("II/90", "I/91", "II/91", "I/92", "II/92", "I/93", "II/93")    
foo %>%
    tibble() %>%
    mutate(year     = gsub(".*/", "", .), 
           monthRom = as.roman(gsub("/.*", "", .))) %>%
    mutate(monthNum = as.numeric(monthRom)) %>%
    mutate(monthChr = month.abb[monthNum])
# A tibble: 7 x 5
      .  year monthRom monthNum monthChr
  <chr> <chr>    <chr>    <dbl>    <chr>
1 II/90    90       II        2      Feb
2  I/91    91        I        1      Jan
3 II/91    91       II        2      Feb
4  I/92    92        I        1      Jan
5 II/92    92       II        2      Feb
6  I/93    93        I        1      Jan
7 II/93    93       II        2      Feb

Or you can simply do this:

foo %>%
    gsub("/.*", "", .) %>%
    as.roman() %>%
    as.numeric() %>%
    month.abb[.]

Use as.roman from utils to transform object into class roman, turn this object into numeric string and extract month from base month.abb.

Parsing custom Dates and Months in Roman Numerals with Tidyverse?

1 Answers1