datefixR

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
library(datefixR)

This vignette describes the functionality of datefixR in more detail than the README file. DatefixR is a lightweight package consisting of two main user-accessible functions, fix_date_char() and fix_date_df(), which converts dates written in different formats into R's built-in Date class. The former is designed to modify character vectors whilst the latter is intended for modifying columns of a data frame (or tibble). fix_date_app() is a third function which allows dates to be standardized via a Shiny app interface. You can learn more about the Shiny app in its dedicated vignette.

Practically, this package is most useful when handling date data which has been supplied via text boxes (instead of a date-specific input with a consistent date format). However, this package may also be useful to validate the format of date data (see date and month imputation).

Usage

Date standardization

Firstly, we will demonstrate date standardization without imputation. We consider a data frame with two columns of dates in differing formats with no missing data.

```{R, echo = TRUE} bad.dates <- data.frame( id = seq(5), some.dates = c( "02/05/92", "01-04-2020", "1996/05/01", "2020-05-01", "02-04-96" ), some.more.dates = c( "01 03 2015", "2nd January 2010", "01/05/1990", "03-Dec-2012", "02 April 2020" ) ) knitr::kable(bad.dates)

`fix_date_df()` requires two arguments, `df`, a data frame (or tibble) object
and `col.names`, a character vector containing the names of columns to be
standardized. By default, the first column of the data frame is assumed to
contain row IDs. These IDs are used if a warning or error is raised to assist
the user with locating the source of the error. The ID column can also be
manually provided via the `id` argument. 

The output from this function is a data frame or tibble (dependent on the
object type of the the first argument, `df`) with the selected date
columns now standardized and belonging to the `Date` class. 

```{R}
fixed.dates <- fix_date_df(
  bad.dates,
  c("some.dates", "some.more.dates")
)
knitr::kable(fixed.dates)

datefixR can handle many different formats including -, /, ., or white space separation, year-first or day-first, and month supplied as a number, an abbreviation or full length name.

fix_date_char() is similar to fix_date_df() but only applies to a single character object.

fix_date_char("01 02 2014")

Localization

datefixR currently supports dates being provided in English, Français (French), Deutsch (German), español (Spanish), and português (Portuguese) by recognizing both names of months in these languages and formatting customs. Expected languages do not need to be specified and can be provided just like any other date to be standardized.

fix_date_char("7 de septiembre del 2014")

Functions in datefixR assume day-first instead of month-first when day, month, and year are all given numerically (unless year is given first). However, this behavior can be modified by passing format = "mdy" to function calls.

fix_date_char("01 02 2014", format = "mdy")

If the month is given by name, then datefixR will automatically detect the correct format without the format argument needing to be specified by the user.

fix_date_char("July 4th, 1776")

Date and month imputation

By default, datefixR imputes missing months as July, and missing days of the month as the first day. As such, "1992" converts to

fix_date_char("1992")

The argument for defaulting to July is 1st-2nd July is halfway through the year (on a non leap year). Therefore, assuming the year supplied is indeed correct, the imputation has a maximum potential error of 6 months from the true date. However, this behavior can be changed by supplying the day.impute and month.impute arguments with an integer corresponding to the desired day and month. For example, day.impute = 1 and month.impute = 1 results in the first day of January being imputed instead which is often a more common imputation for missing date data.

fix_date_char("1992", day.impute = 1, month.impute = 1)

The imputation mechanism can also be modified to impute NA if a month or day is missing by setting day.impute or month.impute to NA. This will also result in a warning being raised.

fix_date_char("1992", month.impute = NA)

Finally, imputation can be prevented by setting day.impute or month.impute to NULL. This will result in an error being raised if the day or month are missing respectively.

```{R, eval = FALSE} fix_date_char("1992", month.impute = NULL)

ERROR

`day.impute` and `month.impute` can also be passed to `fix_date_df()` for
similar functionality. 

```{R}
example.df <- data.frame(
  id = seq(1, 3),
  some.dates = c("2014", "April 1990", "Mar 19")
)
fix_date_df(example.df, "some.dates", day.impute = 1, month.impute = 1)

Citation

If you use this package in your research, please consider citing datefixR. An up-to-date citation can be obtained by running

citation("datefixR")


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datefixR documentation built on Oct. 24, 2022, 5:08 p.m.