Converting dates before January 1, 1970 in R -

i trying convert column of dates date objects in r, can't seem desired results. these individuals have birth dates before january 1, 1970, when use as.date r converts date 1/12/54, example, 2054-01-12. how can work around this? much.

if in 1900s, one-liner - format two-digit year @ start , slap 19 on front , convert date. again. man cool %>% stuff:

s = c("1/12/54","1/12/74") as.date(format(as.date(s,format="%d/%m/%y"), "19%y%m%d"), "%y%m%d") # [1] "1954-12-01" "1974-12-01" 

if years "69" "99" 1800s, here's one-liner:

library(dplyr) # pipe operator: s %>% as.date(format="%d/%m/%y") %>%       format("%y%m%d") %>%     (function(d){        paste0(ifelse(d>700101,"18","19"),d)        }) %>%    as.date("%y%m%d")  ## [1] "1954-12-01" "1874-12-01" 

note not thoroughly tested might off-by-one errors or i've mixed months , days because need iso8601 compliant