如果您希望按字母数字顺序对实际因子进行排序,则可以按这种方式对其进行排序。
location <- c("new_south_wales", "victoria", "queensland")
factor(sort(location))
# [1] new_south_wales queensland victoria
# Levels: new_south_wales queensland victoria
当然,您可以在创建它之前或之后执行此操作。
states <- factor(location)
states
# [1] new_south_wales victoria queensland
# Levels: new_south_wales queensland victoria
sort(states)
# [1] new_south_wales queensland victoria
# Levels: new_south_wales queensland victoria
ordered_states <- sort(states)
ordered_states
# [1] new_south_wales queensland victoria
# Levels: new_south_wales queensland victoria
您也可以按其他顺序订购它们:
states <- factor(location[c(3, 2, 1])
states
# [1] queensland victoria new_south_wales
# Levels: new_south_wales queensland victoria
# Or after the fact:
states <- factor(states[c(3, 1, 2])
states
# [1] victoria queensland new_south_wales
# Levels: new_south_wales queensland victoria
# Notice that this reorders the reordered states, because that's how
# states was last assigned.
默认情况下,级别按字母数字排序,但这对因子中值的实际顺序没有影响(如您所演示的)。
正如您还演示的,有序因子不一定按顺序显示。这只是意味着这些值是有序的