R 将日期转换为错误格式（年份为 5 位数字）

Question

I have loaded a txt dataset into R. A part of it can be seen below:

date    rf
1   19620102 0.011
2   19620103 0.011
3   19620104 0.011
4   19620105 0.011
5   19620108 0.011

I have tried to convert the dates using the following code:

df$date <- format(as.Date(df$date), "%Y-%m-%d")

This gives the following results, that are not what I wanted:

date    rf
1   55688-01-06 0.011
2   55688-01-07 0.011
3   55688-01-08 0.011
4   55688-01-09 0.011
5   55688-01-12 0.011

I wanted to convert the dates into the format as seen below:

date    rf
1   1962-01-02 0.011
2   1962-01-03 0.011
3   1962-01-04 0.011
4   1962-01-05 0.011
5   1962-01-08 0.011

Does anyone know how I can get the results that I want?

Answer 1

This works

as.Date("19620102", "%Y%m%d")
#> [1] "1962-01-02"

^{Created on 2021-02-06 by the reprex package (v0.3.0)}

So just do

as.Date(as.character(df$date), "%Y%m%d")

Answer 2

We could also use ymd from lubridate

library(lubridate)
ymd(19620102)
#[1] "1962-01-02"