CODEWITHSUNDEEP
rdate
AVT
AVT

Reputation: 119

Add Month and Year column from complete date column

I have a column with date formatted as MM-DD-YYYY, in the Date format. I want to add 2 columns one which only contains YYYY and the other only contains MM.

How do I do this?

Upvotes: 2

Views: 15827

Answers (2)

akrun
akrun

Reputation: 887851

A base R option would be to remove the substring with sub and then read with read.table

df1[c('month', 'year')] <- read.table(text=sub("-\\d{2}-", ",", df1$date), sep=",")

Or using tidyverse

library(tidyverse)
separate(df1, date, into = c('month', 'day', 'year') %>% 
           select(-day)

Note: it may be better to convert to datetime class instead of using the string formatting.

df1 %>%
     mutate(date =mdy(date), month = month(date), year = year(date))

data

df1 <- data.frame(date = c("05-21-2017", "06-25-2015"))

Upvotes: 1

Dirk is no longer here
Dirk is no longer here

Reputation: 368539

Once again base R gives you all you need, and you should not do this with sub-strings.

Here we first create a data.frame with a proper Date column. If your date is in text format, parse it first with as.Date() or my anytime::anydate() (which does not need formats).

Then given the date creating year and month is simple:

R> df <- data.frame(date=Sys.Date()+seq(1,by=30,len=10))
R> df[, "year"] <- format(df[,"date"], "%Y")
R> df[, "month"] <- format(df[,"date"], "%m")
R> df
         date year month
1  2017-12-29 2017    12
2  2018-01-28 2018    01
3  2018-02-27 2018    02
4  2018-03-29 2018    03
5  2018-04-28 2018    04
6  2018-05-28 2018    05
7  2018-06-27 2018    06
8  2018-07-27 2018    07
9  2018-08-26 2018    08
10 2018-09-25 2018    09
R>

If you want year or month as integers, you can wrap as as.integer() around the format.

Upvotes: 11

Related Questions