Filter by Date throws error (Error in filter_impl(.data, quo) : Evaluation error: character string is not in a standard unambiguous format.)

[yogat3ch]

This may be related to #2432 .
Fairly simple operation, filtering a data.frame by a column named via a variable using rlang's !! with Dates/POSIXct causes the following error:
Error in filter_impl(.data, quo) : Evaluation error: character string is not in a standard unambiguous format.

test <- data.frame(time = seq(lubridate::today() - lubridate::days(30), lubridate::today(), by = "day"), n = rnorm(31))
td_nm <- stringr::str_extract(names(test), "^time$|^date$") %>% subset(subset = !is.na(.)) %>% .[1]
test %>% dplyr::select((!!td_nm))
# works fine
test %>% dplyr::filter((!!td_nm) > {lubridate::today() - lubridate::days(7)})
# Error

[cderv]

I think you don't use !! correctly here and the error is expected. !!td_nm result in a string and this won't work in filter. I see too correct use here:

• Using filter_at() variant as your column name is a string
• Using sym() on td_nm to create a symbol from a string and the !! on this
  Here examples for those solutions

library(magrittr)
test <- data.frame(time = seq(lubridate::today() - lubridate::days(30), lubridate::today(), by = "day"), n = rnorm(31))
td_nm <- stringr::str_extract(names(test), "^time$|^date$") %>% 
  subset(subset = !is.na(.)) %>% 
  .[1]
# using filter_at variant is useful in this case
test %>% 
  dplyr::filter_at(td_nm, ~ . > {lubridate::today() - lubridate::days(7)})
#>         time          n
#> 1 2019-07-17  1.9963029
#> 2 2019-07-18  0.7997336
#> 3 2019-07-19 -0.7399006
#> 4 2019-07-20  1.7780947
#> 5 2019-07-21  0.7578848
#> 6 2019-07-22 -1.1845520
#> 7 2019-07-23 -0.2126693
# you need sym here
test %>% dplyr::filter(!!dplyr::sym(td_nm) > {lubridate::today() - lubridate::days(7)})
#>         time          n
#> 1 2019-07-17  1.9963029
#> 2 2019-07-18  0.7997336
#> 3 2019-07-19 -0.7399006
#> 4 2019-07-20  1.7780947
#> 5 2019-07-21  0.7578848
#> 6 2019-07-22 -1.1845520
#> 7 2019-07-23 -0.2126693

^{Created on 2019-07-23 by the reprex package (v0.3.0)}

Hope it helps.

[yogat3ch]

Thanks! I understand what was going wrong now! Much appreciated @cderv

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