Convert integer as “20160119” to different columns of “day” “year” “month”

Question

How can I convert a column of integers as dates:

       DATE PRCP
1: 19490101   25
2: 19490102    5
3: 19490118   18
4: 19490119  386
5: 19490202   38
         


        

Answer 1

Another option would be to use separate from the tidyr package:

library(tidyr)
separate(df, DATE, c('year','month','day'), sep = c(4,6), remove = FALSE)

which results in:

       DATE year month day PRCP
1: 19490101 1949    01  01   25
2: 19490102 1949    01  02    5
3: 19490118 1949    01  18   18
4: 19490119 1949    01  19  386
5: 19490202 1949    02  02   38

---

Two options in base R:

1) with substr as said by @coffeinjunky in the comments:

df$year <- substr(df$DATE,1,4)
df$month <- substr(df$DATE,5,6)
df$day <- substr(df$DATE,7,8)

2) with as.Date and format:

df$DATE <- as.Date(as.character(df$DATE),'%Y%m%d')
df$year <- format(df$DATE, '%Y')
df$month <- format(df$DATE, '%m')
df$day <- format(df$DATE, '%d')