fix_date_char: Convert non-standardized dates to R's 'Date' class

In datefixR: Standardize Dates in Different Formats or with Missing Data

Convert non-standardized dates to R's Date class

Description

Converts a character vector (or single character object) from inconsistently formatted dates to R's Date class. Supports numerous separators including /, -, ., or space. Supports numeric, abbreviation, or long-hand month notation in multiple languages (English, French, German, Spanish, Portuguese, Russian, Czech, Slovak, Indonesian). Where day of the month has not been supplied, the first day of the month is imputed by default. Either DMY or YMD is assumed by default. However, the US system of MDY is supported via the format argument.

Usage

fix_date_char(
  dates,
  day.impute = 1,
  month.impute = 7,
  format = "dmy",
  excel = FALSE,
  roman.numeral = FALSE
)

Arguments

dates	Character vector to be converted to R's date class.
day.impute	Integer between 1 and 31, or NA, or NULL. Day of the month to be imputed when missing. Defaults to 1. If day.impute = NA, then NA will be imputed for the date and a warning will be raised. If day.impute = NULL, the function will fail with an error when day is missing.
month.impute	Integer between 1 and 12, or NA, or NULL. Month to be imputed when missing. Defaults to 7 (July). If month.impute = NA, then NA will be imputed for the entire date and a warning will be raised. If month.impute = NULL, the function will fail with an error when month is missing.
format	Character string specifying date interpretation preference. Either "dmy" (day-month-year, default) or "mdy" (month-day-year, US format). This setting only affects ambiguous numeric dates like "01/02/2023". When month names are present or year appears first, the format is auto-detected regardless of this parameter. Note that unambiguous dates (e.g., "25/12/2023") are parsed correctly regardless of the format setting.
excel	Logical: Assumes FALSE by default. If TRUE, treats numeric-only dates with more than four digits as Excel serial dates with 1900-01-01 origin, correcting for known Excel date discrepancies.
roman.numeral	Logical: Defaults to FALSE. When TRUE, attempts to interpret Roman numeral month indications within datasets. This feature may not handle all cases correctly.

Details

This function intelligently parses dates by:

• Handling mixed separators within the same dataset

• Recognizing month names in multiple languages

• Converting Roman numeral months (experimental)

• Processing Excel serial date numbers

• Automatically detecting YMD format when year appears first

• Smart imputation of missing date components with user control

For comprehensive examples and advanced usage, see browseVignettes("datefixR") or the package README at https://docs.ropensci.org/datefixR/.

Value

A vector of elements belonging to R's built in Date class with the following format yyyy-mm-dd.

See Also

fix_date_df for data frame columns with date data.

For detailed examples and usage patterns, see:

• Package vignette: browseVignettes("datefixR")

• Online documentation: https://docs.ropensci.org/datefixR/articles/datefixR.html

• Package README: https://docs.ropensci.org/datefixR/

Examples

# Basic usage
bad.date <- "02 03 2021"
fix_date_char(bad.date)

# Multiple formats with different separators
mixed_dates <- c(
  "02/05/92", # slash separator, 2-digit year
  "2020-may-01", # hyphen separator, text month
  "1996.05.01", # dot separator
  "02 04 96", # space separator
  "le 3 mars 2013" # French format
)
fix_date_char(mixed_dates)

# Text months in different languages
text_months <- c(
  "15 January 2020", # English
  "15 janvier 2020", # French
  "15 Januar 2020", # German
  "15 enero 2020", # Spanish
  "15 de janeiro de 2020" # Portuguese
)
fix_date_char(text_months)

# Roman numeral months (experimental)
roman_dates <- c("15.VII.2023", "3.XII.1999", "1.I.2000")
fix_date_char(roman_dates, roman.numeral = TRUE)

# Excel serial numbers
excel_serials <- c("44197", "44927") # Excel dates
fix_date_char(excel_serials, excel = TRUE)

# Two-digit years (automatic century detection)
two_digit_years <- c("15/03/99", "15/03/25", "15/03/50")
fix_date_char(two_digit_years) # 1999, 2025, 1950

# MDY format (US style)
us_dates <- c("12/25/2023", "07/04/1776", "02/29/2020")
fix_date_char(us_dates, format = "mdy")

# Incomplete dates with custom imputation
incomplete <- c("2023", "March 2022", "June 2021")
fix_date_char(incomplete, day.impute = 15, month.impute = 6)

datefixR documentation built on April 27, 2026, 5:07 p.m.