Utility functions
Several utility functions exported for convenience.
min_or_na(x) max_or_na(x) is_val(x, val) not_val(x, val) is_true(x) is_false(x) last_elem(x) first_elem(x) replace_na(x, val, ...)
x |
Object to use |
val |
Value to compare against |
... |
Forwarded to other methods |
The two functions min_or_na() and max_or_na() overcome a design choice
of base::min() (or base::max()) that can yield undesirable results. If called on a vector of all missing values with na.rm = TRUE, Inf(and-Infrespectively) are returned. This is changed to returning a missing value of the same type asx'.
The functions is_val() and not_val() (as well as analogously
is_true() and is_false()) return logical vectors of the same length as
the value passed as x, with non-base R semanticists of comparing against
NA: instead of returning c(NA, TRUE) for c(NA, 5) == 5, is_val()
will return c(FALSE TRUE). Passing NA as val might lead to unintended
results but no warning is thrown.
Finally, first_elem() and last_elem() has the same semantics as
utils::head() and utils::tail() with n = 1L and replace_na() will
replace all occurrences of NA in x with val and can be called on both
objects inheriting from data.table in which case internally
data.table::setnafill() is called or other objects.
min_or_na()/max_or_na(): scalar-valued extrema of a vector
is_val()/not_val()/is_true()/is_false(): Logical vector of the
same length as the object passed as x
first_elem()/last_elem(): single element of the object passed as x
replace_na(): modified version of the object passed as x
some_na <- c(NA, sample(1:10, 5), NA) identical(min(some_na, na.rm = TRUE), min_or_na(some_na)) all_na <- rep(NA, 5) min(all_na, na.rm = TRUE) min_or_na(all_na) is_val(some_na, 5) some_na == 5 is_val(some_na, NA) identical(first_elem(letters), head(letters, n = 1L)) identical(last_elem(letters), tail(letters, n = 1L)) replace_na(some_na, 11) replace_na(all_na, 11) replace_na(1:5, 11) tbl <- ts_tbl(a = 1:10, b = hours(1:10), c = c(NA, 1:5, NA, 8:9, NA)) res <- replace_na(tbl, 0) identical(tbl, res)
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