R: How to remove the day from a date?

Question

I have a bunch of dates in a df column in the following format: dd.mm.yyyy

I want it to look like this: 01/2020 (mm.yyyy)

How can I remove the day from all of the dates?

Does this answer your question? [Format Date to Year-Month in R](https://stackoverflow.com/questions/50338191/format-date-to-year-month-in-r) — mnist, Apr 30 '20 at 21:24

Greg · Answer 1 · 2020-04-30T21:41:51.450

5

Use format to specify the date format you'd like

date <- as.Date("13/01/2020", format = "%d/%m/%Y")
format(date, "%m/%Y")
[1] "01/2020"

Edit - applying to dataframe column

dates <- c("13/01/2020", "17/02/2015", "13/03/2013")
df <- data.frame(dates, stringsAsFactors = FALSE)
df$dates <- as.Date(df$dates, format = "%d/%m/%Y")
df$dates_format <- format(df$dates, "%m/%Y")
df
       dates dates_format
1 2020-01-13      01/2020
2 2015-02-17      02/2015
3 2013-03-13      03/2013

edited Apr 30 '20 at 21:41

answered Apr 30 '20 at 21:20

Greg

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I have a lot of different dates in the column, so this code only changes dates matching 13/01/2020, is there any way to make it applicable to all dates in the column?? – sjoelly Apr 30 '20 at 21:30
@sjoelly - yes, see edit – Greg Apr 30 '20 at 21:35

score 2 · Accepted Answer · answered Apr 30 '20 at 21:25

2

Besides format by @Greg, another option is using sub like below

> sub(".*?/","","13/01/2020")
[1] "01/2020"

answered Apr 30 '20 at 21:25

ThomasIsCoding

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Why should I use a string manipulation/regex when working with dates? – mnist Apr 30 '20 at 21:26
@mnist Just another way to show the desired result, although it's not ``date` type... – ThomasIsCoding Apr 30 '20 at 21:33
I have a bunch of different dates in the column, not only 13/01/2020, how can i make the code applicable to all dates in the column? sorry didn't make that clear in my question – sjoelly Apr 30 '20 at 21:34
1

It just looks like an overkill to me when we can just use format. Might still be helpful for OP though – mnist Apr 30 '20 at 21:35
@mnist the output of `format` is also a character string, not `date` type – Greg Apr 30 '20 at 21:36
1

@sjoelly you can try `sub(".*?/","",df$date)` – ThomasIsCoding Apr 30 '20 at 21:37

score 2 · Answer 3 · answered Apr 30 '20 at 21:39

Here is a solution using lubridate.

library(lubridate)

#Set the desired format (mm-yyyy) as my_stamp
my_stamp<-stamp( "02-2019", 
                 orders = "my") 

#A df with a column full of dates
df <- data.frame(dates = c("30/04/2020","29/03/2020","28/02/2020"))

#Change the column from string to date format
df$dates<-dmy(df$dates)

#Apply the format you desire to the dates (i.e., only month and year)
df$dates<-my_stamp(df$dates)

#    dates
#1 04-2020
#2 03-2020
#3 02-2020

Cliff Bueno · Answer 4 · 2020-04-30T21:39:48.687

0

There are explicit date formatting options in R (see answer by Greg). Another option would be to separate the date into 3 columns, and then recombine the month and year, putting a / in between. Note this leaves the new date column in character format, which you may want to change depending on your needs.

library(tidyr)
df <- data.frame(date = "13/01/2020")
df <- separate(df, date, into = c("day","month","year"), sep = "/")
df$newdate <- paste(df$month, df$year, sep = "/")

edited Apr 30 '20 at 21:39

answered Apr 30 '20 at 21:30

Cliff Bueno

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Greg's answer should be the accepted answer. the sub and separate options are just other ways to do it. – Cliff Bueno Apr 30 '20 at 21:38

R: How to remove the day from a date?

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