`parse_vector()` error when using mutate_at in pivot vignette in R

June 8, 2023

I was reading the pivot vignette and there is a chunk that when I run resulted in an error. I would appreciate if someone could help me with this issue.

family <- tribble(
  ~family,  ~dob_child1,  ~dob_child2, ~gender_child1, ~gender_child2,
  1L, "1998-11-26", "2000-01-29",             1L,             2L,
  2L, "1996-06-22",           NA,             2L,             NA,
  3L, "2002-07-11", "2004-04-05",             2L,             2L,
  4L, "2004-10-10", "2009-08-27",             1L,             1L,
  5L, "2000-12-05", "2005-02-28",             2L,             1L,
)

family <- family %>% mutate_at(vars(starts_with("dob")), parse_date)

error:

#Error in `mutate()`:
#i In argument: `dob_child1 = (function (x, format = "", na = c("", "NA"),
  #locale = default_locale(), ...`.
#Caused by error in `parse_vector()`:
#! is.character(x) is not TRUE

>Solution :

I suspect the problem is caused by not renaming the ‘family’ dataframe after you make changes to it. Also note that mutate_at() is deprecated and you can use mutate(across()) in it’s place, e.g.

library(tidyverse)

family <- tribble(
  ~family,  ~dob_child1,  ~dob_child2, ~gender_child1, ~gender_child2,
  1L, "1998-11-26", "2000-01-29",             1L,             2L,
  2L, "1996-06-22",           NA,             2L,             NA,
  3L, "2002-07-11", "2004-04-05",             2L,             2L,
  4L, "2004-10-10", "2009-08-27",             1L,             1L,
  5L, "2000-12-05", "2005-02-28",             2L,             1L,
)

family <- family %>% mutate_at(vars(starts_with("dob")), parse_date)
family
#> # A tibble: 5 × 5
#>   family dob_child1 dob_child2 gender_child1 gender_child2
#>    <int> <date>     <date>             <int>         <int>
#> 1      1 1998-11-26 2000-01-29             1             2
#> 2      2 1996-06-22 NA                     2            NA
#> 3      3 2002-07-11 2004-04-05             2             2
#> 4      4 2004-10-10 2009-08-27             1             1
#> 5      5 2000-12-05 2005-02-28             2             1

# Run it again
family <- family %>% mutate_at(vars(starts_with("dob")), parse_date)
#> Error in `mutate()`:
#> ℹ In argument: `dob_child1 = (function (x, format = "", na = c("",
#>   "NA"), locale = default_locale(), ...`.
#> Caused by error in `parse_vector()`:
#> ! is.character(x) is not TRUE
#> Backtrace:
#>      ▆
#>   1. ├─family %>% mutate_at(vars(starts_with("dob")), parse_date)
#>   2. ├─dplyr::mutate_at(., vars(starts_with("dob")), parse_date)
#>   3. │ ├─dplyr::mutate(.tbl, !!!funs)
#>   4. │ └─dplyr:::mutate.data.frame(.tbl, !!!funs)
#>   5. │   └─dplyr:::mutate_cols(.data, dplyr_quosures(...), by)
#>   6. │     ├─base::withCallingHandlers(...)
#>   7. │     └─dplyr:::mutate_col(dots[[i]], data, mask, new_columns)
#>   8. │       └─mask$eval_all_mutate(quo)
#>   9. │         └─dplyr (local) eval()
#>  10. ├─readr (local) `<fn>`(dob_child1)
#>  11. │ └─readr::parse_vector(...)
#>  12. │   └─base::stopifnot(is.character(x))
#>  13. │     └─base::stop(simpleError(msg, call = if (p <- sys.parent(1L)) sys.call(p)))
#>  14. └─dplyr (local) `<fn>`(`<smplErrr>`)
#>  15.   └─rlang::abort(message, class = error_class, parent = parent, call = error_call)

## start from scratch ##
family <- tribble(
  ~family,  ~dob_child1,  ~dob_child2, ~gender_child1, ~gender_child2,
  1L, "1998-11-26", "2000-01-29",             1L,             2L,
  2L, "1996-06-22",           NA,             2L,             NA,
  3L, "2002-07-11", "2004-04-05",             2L,             2L,
  4L, "2004-10-10", "2009-08-27",             1L,             1L,
  5L, "2000-12-05", "2005-02-28",             2L,             1L,
)

output1 <- family %>% mutate_at(vars(starts_with("dob")), parse_date)
output1
#> # A tibble: 5 × 5
#>   family dob_child1 dob_child2 gender_child1 gender_child2
#>    <int> <date>     <date>             <int>         <int>
#> 1      1 1998-11-26 2000-01-29             1             2
#> 2      2 1996-06-22 NA                     2            NA
#> 3      3 2002-07-11 2004-04-05             2             2
#> 4      4 2004-10-10 2009-08-27             1             1
#> 5      5 2000-12-05 2005-02-28             2             1

# 'across' syntax
output2 <- family %>% mutate(across(starts_with("dob"), parse_date))
output2
#> # A tibble: 5 × 5
#>   family dob_child1 dob_child2 gender_child1 gender_child2
#>    <int> <date>     <date>             <int>         <int>
#> 1      1 1998-11-26 2000-01-29             1             2
#> 2      2 1996-06-22 NA                     2            NA
#> 3      3 2002-07-11 2004-04-05             2             2
#> 4      4 2004-10-10 2009-08-27             1             1
#> 5      5 2000-12-05 2005-02-28             2             1

all.equal(output1, output2)
#> [1] TRUE

^{Created on 2023-06-08 with reprex v2.0.2}