Convert Data Frame Column to Date in R

If we have an integer column that actually contains date values, for example having 29th September 2020 as 20200929 then we can convert it to date by using transform function by reading the dates with as.Date function but as.character will also be needed so that as.Date function can read the date values.

Example1

 Live Demo

Consider the below data frame −

ID<−1:20
Dates<−c(20200101, 20200401, 20201015, 20200111, 20200222, 20200121, 20200701, 20201231, 20200417, 20200601, 20200811, 20200927, 20200512, 20200713, 20200225, 20200324, 20200203, 20200819, 20200916, 20200428)
df1<−data.frame(ID,Dates)
df1

Output

   ID    Dates
1 1 20200101
2 2 20200401
3 3 20201015
4 4 20200111
5 5 20200222
6 6 20200121
7 7 20200701
8 8 20201231
9 9 20200417
10 10 20200601
11 11 20200811
12 12 20200927
13 13 20200512
14 14 20200713
15 15 20200225
16 16 20200324
17 17 20200203
18 18 20200819
19 19 20200916
20 20 20200428

Converting Dates to appropriate date format −

df1<−transform(df1,Dates=as.Date(as.character(Dates),"%Y%m%d"))
df1

Output

   ID    Dates
1 1 2020−01−01
2 2 2020−04−01
3 3 2020−10−15
4 4 2020−01−11
5 5 2020−02−22
6 6 2020−01−21
7 7 2020−07−01
8 8 2020−12−31
9 9 2020−04−17
10 10 2020−06−01
11 11 2020−08−11
12 12 2020−09−27
13 13 2020−05−12
14 14 2020−07−13
15 15 2020−02−25
16 16 2020−03−24
17 17 2020−02−03
18 18 2020−08−19
19 19 2020−09−16
20 20 2020−04−28

Example2

 Live Demo

S.NO<−1:20
Date<−c(19980313, 19980604, 19980409, 19980104, 19980501, 19980101, 19980521, 19980412, 19980601, 19980711, 19980615, 19980810, 19980509, 19980221, 19981101, 19981121, 19981009, 19980915, 19980929, 19980813)
df2<−data.frame(S.NO,Date)
df2

Output

   S.NO    Date
1 1 19980313
2 2 19980604
3 3 19980409
4 4 19980104
5 5 19980501
6 6 19980101
7 7 19980521
8 8 19980412
9 9 19980601
10 10 19980711
11 11 19980615
12 12 19980810
13 13 19980509
14 14 19980221
15 15 19981101
16 16 19981121
17 17 19981009
18 18 19980915
19 19 19980929
20 20 19980813

Converting Date to appropriate date format −

df2<−transform(df2,Date=as.Date(as.character(Date),"%Y%m%d"))
df2

Output

   S.NO    Date
1 1 1998−03−13
2 2 1998−06−04
3 3 1998−04−09
4 4 1998−01−04
5 5 1998−05−01
6 6 1998−01−01
7 7 1998−05−21
8 8 1998−04−12
9 9 1998−06−01
10 10 1998−07−11
11 11 1998−06−15
12 12 1998−08−10
13 13 1998−05−09
14 14 1998−02−21
15 15 1998−11−01
16 16 1998−11−21
17 17 1998−10−09
18 18 1998−09−15
19 19 1998−09−29
20 20 1998−08−13