r - 如何通过改变数据的配置来删除数据帧的NA？

Question

所以我有一个像这样的数据框，其中包含三个国家/地区存在的物种名称，以及不存在某个物种的国家/地区的一些 NA:

     Country_A      |      Country_B      |    Country_C   
-----------------------------------------------------
Tilapia guineensis  |         NA          | Tilapia guineensisi
Tilapia zillii      | Tilapia zillii      | Tilapia zillii
       NA           | Fundulus rubrifrons |  Fundulus rubrifrons
Eutrigla gurnardus  | Eutrigla gurnardus  |       NA
Sprattus sprattus   |         NA          |       NA

我想做的基本上是检查一个物种是否存在于一个、两个或三个国家，并制作一个数据框，如下所示:

     Species name   |      Country_A     |    Country_B    | Country_C 
---------------------------------------------------------------------
Tilapia guineensis  |      present       |   not_present   | present
Tilapia zillii      |      present       |   present       | present
Fundulus rubrifrons |     not_present    |   present       | present 
Eutrigla gurnardus  |      present       |   present       | not_present
Sprattus sprattus   |      present       |   not_present   | not_present

我认为也许使用扩展函数或 ifelse 函数可能是一种方法，但我真的不知道如何实现它。非常感谢您的回答

Answer 1

这里是一个带有 is.na 的选项。使用lapply循环数据集的列，使用is.na创建逻辑向量，将其转换为数字索引，用字符串向量替换值并绑定(bind)它们进入使用 coalesce

创建的 transmuteed 'Species_name' 列

lst1 <- lapply(df1, function(x) c("present", "not_present")[1 + is.na(x)])

library(dplyr)
df1 %>%
    transmute(Species_name = coalesce(!!! .)) %>%
    bind_cols(lst1)

-输出

#         Species_name   Country_A   Country_B   Country_C
#1  Tilapia guineensis     present not_present     present
#2      Tilapia zillii     present     present     present
#3 Fundulus rubrifrons not_present     present     present
#4  Eutrigla gurnardus     present     present not_present
#5   Sprattus sprattus     present not_present not_present

---

或者，如果我们只想在 tidyverse 上执行此操作，则可以选择仅使用 dplyr 并且更紧凑

df1 %>% 
     mutate(Species_name = coalesce(!!! .),
        across(starts_with('Country'), 
                  ~c("present", "not_present")[1 + is.na(.)]))
#    Country_A   Country_B   Country_C        Species_name
#1     present not_present     present  Tilapia guineensis
#2     present     present     present      Tilapia zillii
#3 not_present     present     present Fundulus rubrifrons
#4     present     present not_present  Eutrigla gurnardus
#5     present not_present not_present   Sprattus sprattus

数据

df1 <- structure(list(Country_A = c("Tilapia guineensis", "Tilapia zillii", 
NA, "Eutrigla gurnardus", "Sprattus sprattus"), Country_B = c(NA, 
"Tilapia zillii", "Fundulus rubrifrons", "Eutrigla gurnardus", 
NA), Country_C = c("Tilapia guineensisi", "Tilapia zillii",
"Fundulus rubrifrons", 
NA, NA)), class = "data.frame", row.names = c(NA, -5L))