I would like to add a date column to my data frame. The date column needs to populate automatically for the full length of the column

Question

I would like to add a date column to a data frame. The date column needs to populate automatically for the full length of the column. See example below:

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Data frame:

df = structure(list(Name = c("Joe", "Sanj", "Rob"), 
                    Col1 = c(20, 60, 40), 
                    Col2 = c(100, 233, 500)),  
               row.names = c(NA, -3L), 
               class = c("tbl_df", "tbl", "data.frame"))

What's the value you want to have? – Aziz Aug 12 '20 at 09:44 — Aziz, Aug 12 '20 at 09:44
any date is ok, just repeated. For example, 12/8/2020 – Montana_innit96 Aug 12 '20 at 09:50 — Montana_innit96, Aug 12 '20 at 09:50
`transform(df, Date = Sys.Date())` ? – Ronak Shah Aug 12 '20 at 09:58 — Ronak Shah, Aug 12 '20 at 09:58
GREAT, THANK YOU MAESTRO! – Montana_innit96 Aug 12 '20 at 10:21 — Montana_innit96, Aug 12 '20 at 10:21

score 0 · Answer 1 · answered Aug 12 '20 at 11:40

You can add Sys.Date() (todays date) as a new column.

df$Date <- Sys.Date()

# A tibble: 3 x 4
#  Name   Col1  Col2 Date      
#  <chr> <dbl> <dbl> <date>    
#1 Joe      20   100 2020-08-12
#2 Sanj     60   233 2020-08-12
#3 Rob      40   500 2020-08-12

score 0 · Answer 2 · answered Aug 12 '20 at 11:45

The simplest way to do this is by doing the following:

df$date <- as.Date("2020-08-12")

This assigns the data value "2020-08-12" to a new column in df called date. When assigning a length 1 vector to a new column of a dataframe, R will recycle to the same length as the columns in your dataframe (3 in this case). We wrap your date ("2020-08-21") in as.Date() so the column class is "date". If we do not do this, the class will be "character".

I would like to add a date column to my data frame. The date column needs to populate automatically for the full length of the column

2 Answers2