Select multiple date columns and convert factor variables to date

Question

I have a data.frame with multiple columns that contain dates. At present they are recognised as "factor" class. I want to select all the columns that should be dates (there are 10 of them, they all have "Date" in their name, e.g. Date_Construc, Date_use, Comp_date...) and convert them from factor to date.

Here's what I've tried: First I want to select the relevant columns in a vector

library(tidyselect)
date_vars <- vars_select(names(df1), contains("Date", ignore.case = TRUE))

then

library(lubridate)
date_vars <- dmy(date_vars)

Also tried

date_vars <- vars_select(names(df1), contains("Date", ignore.case = TRUE))
df1[date_vars] <- lapply(df1[date_vars], as.Date)

I get

 Error in as.Date.numeric(X[[i]], ...) : 'origin' must be supplied

Also

date_vars <- vars_select(names(df1), contains("Date", ignore.case = TRUE))
df1[date_vars] <- dmy(as.character(df1[date_vars])

with result,

 Warning message:
All formats failed to parse. No formats found.

This is sample data in current format:

Date_Construct= c("10/03/2018 00:00", "21/03/2015 00:00", "20/02/2012 00:00")
Date_use = c("02/08/2007 00:00", "31/10/2007 00:00", "13/08/2008 00:00")
ID = c("0001", "34560", "100041531")
Comp = c("Revis", "Succ", "Revis")

dfq= data.frame(`ID`, `Date_Construct`, `Date_use`, `Comp`)



    ID      Date_Construct     Date_use            Comp
1   0001    10/03/2018 00:00    02/08/2007 00:00    Revis
2   34560   21/03/2015 00:00    31/10/2007 00:00    Succ
3   100041531   20/02/2012 00:00    13/08/2008 00:00    Revis

semaphorism semaphorism · Accepted Answer · 2020-10-28T11:08:53

Updated answer based on new data provided.

Try the following. There's no need to strip out the time component of the date-time string. You can parse it using the lubridate function which matches the data (in this case, dmy_hm()) then disregard it.

dfq_parsed <- dfq %>%
  mutate(across(contains("date", ignore.case = TRUE), dmy_hm))

This yields:

         ID Date_Construct   Date_use  Comp
1      0001     2018-03-10 2007-08-02 Revis
2     34560     2015-03-21 2007-10-31  Succ
3 100041531     2012-02-20 2008-08-13 Revis

Where the dates are as POSIXct, but that's easy enough to work with:

'data.frame':   3 obs. of  4 variables:
 $ ID            : chr  "0001" "34560" "100041531"
 $ Date_Construct: POSIXct, format: "2018-03-10" "2015-03-21" "2012-02-20"
 $ Date_use      : POSIXct, format: "2007-08-02" "2007-10-31" "2008-08-13"
 $ Comp          : chr  "Revis" "Succ" "Revis"

Select multiple date columns and convert factor variables to date

1 Answers