# Warning: all onset_date values converted to NA

R code
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1

Hello , my Problem is:converting onset_date column to Date in R

I am trying to convert the `onset_date` column in my dataset to Date type using:

install and load packages

pacman::p_load(janitor, tidyverse, reprex, datapasta, lubridate)

minimal dataset

surv_raw ← data.frame(
stringsAsFactors = FALSE,
onset_date = c(“2014-12-01”, “2014-12-02”, “invalid_date”, “32-12-2014”, “2014-13-05”)
)

try to convert column to Date

surv_clean ← surv_raw %>%
clean_names() %>%
mutate(onset_date = ymd(onset_date))
#> Warning: There was 1 warning in `mutate()`.
#> :information_source: In argument: `onset_date = ymd(onset_date)`.
#> Caused by warning:
#> ! 3 failed to parse.

check the cleaned date column

class(surv_clean$onset_date)
#> [1] “Date”
range(surv_clean$onset_date)
#> [1] NA NA

Created on 2026-03-11 with reprex v2.1.1

2

Hello,

In this case, the error message provided indicates that three onset dates failed to parse. You can see that there is one whose value is “invalid_date”, one whose value is the impossible date “32-12-2014”, and one whose format is presumably YDM rather than YMD “2014-13-05”.

You would need to address these issues prior to calling the ymd function or use a different approach that can handle these aberrant onset dates.

All the best,

Tim

3

Adding to Tim’s resopnse. Yes, ymd() is working as expected here: it successfully converts the valid dates and turns the invalid ones into NA.

In your example:

onset_date = c("2014-12-01", "2014-12-02", "invalid_date", "32-12-2014", "2014-13-05")

only the first two are valid YYYY-MM-DD dates.

So after:

mutate(onset_date = ymd(onset_date))

you get a Date column with some NAs.

Why range() returns NA NA

Because range() does not ignore missing values unless you tell it to:

range(surv_clean$onset_date)
# [1] NA NA

Use:

range(surv_clean$onset_date, na.rm = TRUE)

Example

pacman::p_load(dplyr,janitor,lubridate)

surv_raw <- data.frame(
  stringsAsFactors = FALSE,
  onset_date = c("2014-12-01", "2014-12-02", "invalid_date", "32-12-2014", "2014-13-05")
)

surv_clean <- surv_raw %>%
  clean_names() %>%
  mutate(onset_date = ymd(onset_date))

surv_clean
#   onset_date
# 1 2014-12-01
# 2 2014-12-02
# 3       <NA>
# 4       <NA>
# 5       <NA>

class(surv_clean$onset_date)
# [1] "Date"

range(surv_clean$onset_date, na.rm = TRUE)
# [1] "2014-12-01" "2014-12-02"

Best,

Luis