Question

我这里有世界各国的数据框：

structure(list(long = c(290.100891113281, 290.104309082031, 290.057800292969, 
289.995849609375, 289.933868408203, 289.949127197266, 289.964874267578, 
290.02685546875, 290.088195800781, 290.100891113281, 74.8913116455078, 
74.8402328491211, 74.7673797607422, 74.7389602661133, 74.7266616821289, 
74.6689453125, 74.5589904785156, 74.3721694946289, 74.3761672973633, 
74.4979553222656), lat = c(12.4520015716553, 12.4229984283447, 
12.4385251998901, 12.50048828125, 12.5469722747803, 12.5970697402954, 
12.6141109466553, 12.567626953125, 12.48046875, 12.4520015716553, 
37.2316398620605, 37.2250518798828, 37.2491722106934, 37.28564453125, 
37.2907218933105, 37.2667007446289, 37.2366218566895, 37.15771484375, 
37.1373519897461, 37.0572242736816), group = c(1, 1, 1, 1, 1, 
1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2), order = c(1L, 2L, 
3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 12L, 13L, 14L, 15L, 16L, 17L, 
18L, 19L, 20L, 21L), region = c("Aruba", "Aruba", "Aruba", "Aruba", 
"Aruba", "Aruba", "Aruba", "Aruba", "Aruba", "Aruba", "Afghanistan", 
"Afghanistan", "Afghanistan", "Afghanistan", "Afghanistan", "Afghanistan", 
"Afghanistan", "Afghanistan", "Afghanistan", "Afghanistan"), 
    subregion = c(NA_character_, NA_character_, NA_character_, 
    NA_character_, NA_character_, NA_character_, NA_character_, 
    NA_character_, NA_character_, NA_character_, NA_character_, 
    NA_character_, NA_character_, NA_character_, NA_character_, 
    NA_character_, NA_character_, NA_character_, NA_character_, 
    NA_character_), population = c(71891L, 71891L, 71891L, 71891L, 
    71891L, 71891L, 71891L, 71891L, 71891L, 71891L, 31056997L, 
    31056997L, 31056997L, 31056997L, 31056997L, 31056997L, 31056997L, 
    31056997L, 31056997L, 31056997L)), .Names = c("long", "lat", 
"group", "order", "region", "subregion", "population"), row.names = c(1L, 
2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 12L, 13L, 14L, 15L, 16L, 
17L, 18L, 19L, 20L, 21L), class = "data.frame")

在数据框的其余部分，有一些国家的NA人口价值。我想要一种方法来插入具有NA人口值的这些国家的人口值。

例如，我想把int的人口值加到美国

world %>% 
  filter(region == "USA") %>% 
  mutate(population = 298444215)

这使得单独的数据帧仅包含USA的数据。但是，我最好只想在我上面输入的整个数据帧中改变美国的人口值！

Answer 1

由于您使用的是dplyr，因此这是一个简单的解决方案：

df <- df %>% 
      mutate(population = case_when(region == "USA" ~ 298444215,
                                TRUE ~ as.double(population)))

您可以将所需的所有国家/地区手动分配人口价值添加到case_when的一次调用中。

Answer 2

不使用任何套餐，我们可以尝试

## find out the index which region is USA and population is NA
index_usa <- which(world$region == "USA" & is.na(world$population))

## fill the population column according to the index
world[index_usa, ]$population <- 298444215

Answer 3

简单的索引适用于带有基础R的单行：

world[, 'population'][world[, 'region'] == 'USA'] <- 298444215

这就是说，大致翻译成英文;

world[, 'population'] 为人口专栏
[world[, 'region'] == 'USA']位于region列为USA的行
<- 298444215插入此值

如何将值放入某些行的数据框中

3 个答案: