attempt is a wrapper around base try that allows you to insert a custom messsage on error.
library(attempt)
attempt(log("a"))
# Error: argument non numérique pour une fonction mathématique
attempt(log("a"), msg = "Nop !")
# Error: Nop !You can make it verbose (i.e. returning the expression):
Of course the result is returned if there is one:
As with try, the result cant be saved as an error object :
a <- attempt(log("a"), msg = "Nop !", verbose = TRUE)
a
#> [1] "Error in log(\"a\"): Nop !\n"
#> attr(,"class")
#> [1] "try-error"
#> attr(,"condition")
#> <simpleError in log("a"): Nop !>
# [1] "Error in log(\"a\"): Nop !\n"
# attr(,"class")
# [1] "try-error"
# attr(,"condition")
# <simpleError in log("a"): Nop !>silent_attempt is a wrapper around silently (see the adverbs vignette for more info) and attempt. It attempts to run the expr, stays silent if the expression succeeds, and returns error or warnings if any.
You can write a try catch with these params :
expr the expression to be evaluated.e a mapper or a function evaluated when an error occurs.w a mapper or a function evaluated when a warning occurs.f a mapper or an expression which is always evaluated before returning or exitingIn .e and .f, the .x refers to the error / warning object.
try_catch(expr = log("a"),
.e = ~ paste0("There is an error: ", .x),
.w = ~ paste0("This is a warning: ", .x))
#> [1] "There is an error: Error in log(\"a\"): argument non numérique pour une fonction mathématique\n"
#[1] "There is an error: Error in log(\"a\"): argument non numérique pour une fonction mathématique\n"
try_catch(log("a"),
.e = ~ stop(.x),
.w = ~ warning(.x))
#> Error in log("a"): argument non numérique pour une fonction mathématique
# Error in log("a") : argument non numérique pour une fonction mathématique
try_catch(matrix(1:3, nrow= 2),
.e = ~ print(.x),
.w = ~ print(.x))
#> <simpleWarning in matrix(1:3, nrow = 2): la longueur des données [3] n'est pas un diviseur ni un multiple du nombre de lignes [2]>
#<simpleWarning in matrix(1:3, nrow = 2): la longueur des données [3] n'est pas un diviseur ni un multiple du nombre de lignes [2]>
try_catch(expr = 2 + 2 ,
.f = ~ print("Using R for addition... ok I'm out!"))
#> [1] "Using R for addition... ok I'm out!"
#> [1] 4
# [1] "Using R for addition... ok I'm out!"
# [1] 4As usual, the handlers are set only if you call them :
try_catch(matrix(1:3, nrow = 2), .e = ~ print("error"))
#> Warning in matrix(1:3, nrow = 2): la longueur des données [3] n'est pas un
#> diviseur ni un multiple du nombre de lignes [2]
#> [,1] [,2]
#> [1,] 1 3
#> [2,] 2 1
# [,1] [,2]
# [1,] 1 3
# [2,] 2 1
# Warning message:
# In matrix(1:3, nrow = 2) :
# la longueur des données [3] n'est pas un diviseur ni un multiple du nombre de lignes [2]{attempt} is flexible in how you can specify your arguments.
You can, as you do with {base} tryCatch, use a plain old function:
try_catch(log("a"),
.e = function(e){
print(paste0("There is an error: ", e))
print("Ok, let's save this")
time <- Sys.time()
a <- paste("+ At",time, ", \nError:",e)
# write(a, "log.txt", append = TRUE) # commented to prevent log.txt creation
print(paste("log saved on log.txt at", time))
print("let's move on now")
})
#> [1] "There is an error: Error in log(\"a\"): argument non numérique pour une fonction mathématique\n"
#> [1] "Ok, let's save this"
#> [1] "log saved on log.txt at 2018-04-20 13:21:29"
#> [1] "let's move on now"
# [1] "There is an error: Error in log(\"a\"): argument non numérique pour une fonction mathématique\n"
# [1] "Ok, let's save this"
# [1] "log saved on log.txt at 2017-12-20 18:24:05"
# [1] "let's move on now"You can even mix both:
try_catch(log("a"),
.e = function(e){
paste0("There is an error: ", e)
},
.f = ~ print("I'm not sure you can do that pal !"))
#> [1] "I'm not sure you can do that pal !"
#> [1] "There is an error: Error in log(\"a\"): argument non numérique pour une fonction mathématique\n"
# [1] "I'm not sure you can do that pal !"
# [1] "There is an error: Error in log(\"a\"): argument non numérique pour une fonction mathématique\n"
try_catch(log("a"),
.e = ~ paste0("There is an error: ", .x),
.f = function() print("I'm not sure you can do that pal !"))
#> [1] "I'm not sure you can do that pal !"
#> [1] "There is an error: Error in log(\"a\"): argument non numérique pour une fonction mathématique\n"
# [1] "I'm not sure you can do that pal !"
# [1] "There is an error: Error in log(\"a\"): argument non numérique pour une fonction mathématique\n"try_catch_df returns a tibble with the call, the error message if any, the warning message if any, and the value of the evaluated expression or “error”. The values will always be contained in a list-column.
res_log <- try_catch_df(log("a"))
res_log
#> call error warning
#> 1 log("a") argument non numérique pour une fonction mathématique NA
#> value
#> 1 error
res_log$value
#> [[1]]
#> [1] "error"
res_matrix <- try_catch_df(matrix(1:3, nrow = 2))
res_matrix
#> call error
#> 1 matrix(1:3, nrow = 2) NA
#> warning
#> 1 la longueur des données [3] n'est pas un diviseur ni un multiple du nombre de lignes [2]
#> value
#> 1 1, 2, 3, 1
res_matrix$value
#> [[1]]
#> [,1] [,2]
#> [1,] 1 3
#> [2,] 2 1
res_success <- try_catch_df(log(1))
res_success
#> call error warning value
#> 1 log(1) NA NA 0
res_success$value
#> [[1]]
#> [1] 0map_try_catch and map_try_catch_df allow you to map on a list of arguments l, to be evaluated by the function in fun.
map_try_catch(l = list(1, 3, "a"), fun = log, .e = ~ .x)
#> [[1]]
#> [1] 0
#>
#> [[2]]
#> [1] 1.098612
#>
#> [[3]]
#> <simpleError in .Primitive("log")("a"): argument non numérique pour une fonction mathématique>
map_try_catch_df(list(1,3,"a"), log)
#> call
#> 1 .Primitive("log")(1)
#> 2 .Primitive("log")(3)
#> 3 .Primitive("log")("a")
#> error warning value
#> 1 <NA> NA 0
#> 2 <NA> NA 1.098612
#> 3 argument non numérique pour une fonction mathématique NA error