Character Vector to (Unordered) Factor
v2fct converts a character vector to a (unordered) factor. It goes
beyond as.factor by allowing you to specify how you want the levels ordered
and whether you want NA treated as a level.
v2fct( v, order.lvl = "position", decreasing = FALSE, na.lvl = FALSE, check = TRUE )
v |
character vector. If it is not a character vector (e.g., factor,
numeric vector), then it is coerced to a character vector within |
order.lvl |
character vector of length 1 specifying how you want to order the levels of the factor. The options are "alphanum", which sorts the levels alphanumerically (with NA last); "position", which sorts the levels by the position the level first appears; "frequency", which sorts the levels by their frequency. If any frequencies are tied, then the ties are sorted alphanumerically (with NA last). |
decreasing |
logical vector of length 1 specifying whether the ordering of the levels should be decreasing (TRUE) rather than increasing (FALSE). |
na.lvl |
logical vector of length 1 specifying if NA should be considered a level. |
check |
logical vector of length 1 specifying whether to check the structure
of the input arguments. For example, check whether |
When order.lvl = "alpanum" the levels are sorted alphabetically if letters
or a combination of letters and numbers/numerals are in present in v.
If only numbers/numerals are present in v, then levels are sorted numerically.
factor of length = length(x) and names = names(x).
# no missing values
state_region <- as.character(state.region)
v2fct(state_region, order.lvl = "position") # in position order
v2fct(v = state_region, order.lvl = "frequency",
decreasing = TRUE) # most frequent to least frequent
v2fct(v = state_region, order.lvl = "alphanum") # in alphanumerical order
v2fct(v = state_region, na.lvl = TRUE) # na.lvl is inert because no NAs in `v`
# with missing values
state_region <- c(NA_character_, as.character(state.region), NA_character_)
v2fct(v = state_region, order.lvl = "position", na.lvl = TRUE)
v2fct(v = state_region, order.lvl = "frequency", decreasing = TRUE, na.lvl = TRUE)
v2fct(v = state_region, order.lvl = "alphanum", na.lvl = TRUE)
identical(x = v2fct(v = state_region, order.lvl = "alphanum"),
y = as.factor(state_region)) # equal to as.factor()
# numeric vectors
v2fct(v = round(faithful$"eruptions"), order.lvl = "position")
v2fct(v = round(faithful$"eruptions"), order.lvl = "frequency", decreasing = TRUE)
v2fct(v = round(faithful$"eruptions"), order.lvl = "alphanum")
# cnumeric vectors
cnum <- c("100","99","10","9","1","0","100","99","10","9","1","0")
factor(cnum) # not in numerical order
v2fct(v = cnum, order.lvl = "alphanum") # yes in numerical order
# ties on frequency
v2fct(v = rev(npk$"block"), order.lvl = "alphanum") # ties sorted alphanumerically
v2fct(v = rev(npk$"block"), order.lvl = "position") # no possibility of tiesPlease choose more modern alternatives, such as Google Chrome or Mozilla Firefox.