Check whether a student defined a certain object (correctly)
check_object(state, name, undefined_msg = NULL, append = TRUE) check_column(state, col, col_missing_msg = NULL, append = TRUE) check_element(state, el, el_missing_msg = NULL, append = TRUE) # S3 method for ObjectState check_equal(state, incorrect_msg = NULL, append = TRUE, eq_condition = "equivalent", eq_fun = NULL, ...) # S3 method for ObjectColumnState check_equal(state, incorrect_msg = NULL, append = TRUE, eq_condition = "equivalent", eq_fun = NULL, ...) # S3 method for ObjectElementState check_equal(state, incorrect_msg = NULL, append = TRUE, eq_condition = "equivalent", eq_fun = NULL, ...)
| state | the state to start from |
|---|---|
| name | name of the object to test. |
| undefined_msg | Optional feedback message in case the student did not define the object. A meaningful message is automatically generated if not supplied. |
| append | Whether or not to append the feedback to feedback built in previous states |
| col | name of column to check |
| col_missing_msg | Custom message in case data frame column is missing |
| el | name of element to check |
| el_missing_msg | Custom message in case element is messing. |
| incorrect_msg | Custom feedback message in case the student's object is not the same as in the sample solution. |
| eq_condition | character string indicating how to compare. See
|
| eq_fun | optional argument to specify a custom equality function. The
function should take two arguments and always return a single boolean
value: |
| ... | S3 stuff |
if (FALSE) { # Example 1 x <- mean(1:3, na.rm = TRUE) # sct to only check existence of x ex() %>% check_object("x") # sct to check existence and equality ex() %>% check_object("x") %>% check_equal() # Example 2 df <- data.frame(a = 1:3, b = LETTERS[1:3]) # sct to test column a ex() %>% check_object("df") %>% check_column("a") %>% check_equal() # Example 3 lst <- list(a = 1, b = 2) # sct to test only element b ex() %>% check_object("lst") %>% check_element("b") %>% check_equal() # Example 4 today <- Sys.Date() # sct to check if classes are equal ex() %>% check_object("today") %>% check_equal(eq_fun = function(x, y) { all.equal(class(x), class(y)) }) }