reorder or swap parts of character value in a dataframe column

[jarle]

Hi
I have ended up with a column in a dataframe with dates in different formats. How should I go about making the last two similar to the first two, i.e. change intervdate format from %y-%m-%d to %d.%m.%y ?

The real dataframe consists of multiple different dataframes (from csv files that for some reason have different date formats)

Thanks for pointing me in the right direction!

df <- data.frame(id = c(1:4),
intervdate = c("2023-07-25", "2023-06-14", "31.01.2020", "25.02.2020"))

[technocrat]

You would be better off using as.Date() to convert them separately, and then combine and set format with

format(dates, format = "%d.%m.%Y")

which allows performing date arithmetic.

However, to just conform the string representation

d <- data.frame(
  id = c(1:4),
  date = c("2023-07-25", "2023-06-14", "31.01.2020", "25.02.2020"))

reformat <- function(x) gsub("(\\d{4})-(\\d{2})-(\\d{2})", "\\3.\\2.\\1", x)

d[grep("^\\d{4}-",d$date),"date"] <- reformat(d[grep("^\\d{4}-",d$date)",date"])
d
#>   id       date
#> 1  1 25.07.2023
#> 2  2 14.06.2023
#> 3  3 31.01.2020
#> 4  4 25.02.2020

^{Created on 2023-10-12 with reprex v2.0.2}

[DavoWW]

Hi @jarle
You could try the package anytime which tries to automatically handle a multitude of date formats.

[jarle]

Thanks!
This solved it , much appreciated!

[jarle]

Thanks! Will try that eventually