R tidyr fill 用上一個或下一個值填充缺失值

使用下一個或上一個條目填充選定列中的缺失值。這在通用輸出格式中非常有用，其中值不重複，並且僅在它們更改時才記錄。

用法

fill(data, ..., .direction = c("down", "up", "downup", "updown"))

參數

data: 一個 DataFrame 。
...: < tidy-select > 要填充的列。
.direction: 填充缺失值的方向。目前是"down"(默認)、"up"、"downup"(即先向下然後向上)或"updown"(先向上然後向下)。

細節

缺失值在原子向量中被替換； NULL 在列表中被替換。

分組 DataFrame

對於 dplyr::group_by() 創建的分組 DataFrame ，fill() 將應用於每個組內，這意味著它不會填充跨越組邊界。

例子

# direction = "down" --------------------------------------------------------
# Value (year) is recorded only when it changes
sales <- tibble::tribble(
  ~quarter, ~year, ~sales,
  "Q1",    2000,    66013,
  "Q2",      NA,    69182,
  "Q3",      NA,    53175,
  "Q4",      NA,    21001,
  "Q1",    2001,    46036,
  "Q2",      NA,    58842,
  "Q3",      NA,    44568,
  "Q4",      NA,    50197,
  "Q1",    2002,    39113,
  "Q2",      NA,    41668,
  "Q3",      NA,    30144,
  "Q4",      NA,    52897,
  "Q1",    2004,    32129,
  "Q2",      NA,    67686,
  "Q3",      NA,    31768,
  "Q4",      NA,    49094
)
# `fill()` defaults to replacing missing data from top to bottom
sales %>% fill(year)
#> # A tibble: 16 × 3
#>    quarter  year sales
#>    <chr>   <dbl> <dbl>
#>  1 Q1       2000 66013
#>  2 Q2       2000 69182
#>  3 Q3       2000 53175
#>  4 Q4       2000 21001
#>  5 Q1       2001 46036
#>  6 Q2       2001 58842
#>  7 Q3       2001 44568
#>  8 Q4       2001 50197
#>  9 Q1       2002 39113
#> 10 Q2       2002 41668
#> 11 Q3       2002 30144
#> 12 Q4       2002 52897
#> 13 Q1       2004 32129
#> 14 Q2       2004 67686
#> 15 Q3       2004 31768
#> 16 Q4       2004 49094

# direction = "up" ----------------------------------------------------------
# Value (pet_type) is missing above
tidy_pets <- tibble::tribble(
  ~rank, ~pet_type, ~breed,
  1L,        NA,    "Boston Terrier",
  2L,        NA,    "Retrievers (Labrador)",
  3L,        NA,    "Retrievers (Golden)",
  4L,        NA,    "French Bulldogs",
  5L,        NA,    "Bulldogs",
  6L,     "Dog",    "Beagles",
  1L,        NA,    "Persian",
  2L,        NA,    "Maine Coon",
  3L,        NA,    "Ragdoll",
  4L,        NA,    "Exotic",
  5L,        NA,    "Siamese",
  6L,     "Cat",    "American Short"
)

# For values that are missing above you can use `.direction = "up"`
tidy_pets %>%
  fill(pet_type, .direction = "up")
#> # A tibble: 12 × 3
#>     rank pet_type breed                
#>    <int> <chr>    <chr>                
#>  1     1 Dog      Boston Terrier       
#>  2     2 Dog      Retrievers (Labrador)
#>  3     3 Dog      Retrievers (Golden)  
#>  4     4 Dog      French Bulldogs      
#>  5     5 Dog      Bulldogs             
#>  6     6 Dog      Beagles              
#>  7     1 Cat      Persian              
#>  8     2 Cat      Maine Coon           
#>  9     3 Cat      Ragdoll              
#> 10     4 Cat      Exotic               
#> 11     5 Cat      Siamese              
#> 12     6 Cat      American Short       

# direction = "downup" ------------------------------------------------------
# Value (n_squirrels) is missing above and below within a group
squirrels <- tibble::tribble(
  ~group,    ~name,     ~role,     ~n_squirrels,
  1,      "Sam",    "Observer",   NA,
  1,     "Mara", "Scorekeeper",    8,
  1,    "Jesse",    "Observer",   NA,
  1,      "Tom",    "Observer",   NA,
  2,     "Mike",    "Observer",   NA,
  2,  "Rachael",    "Observer",   NA,
  2,  "Sydekea", "Scorekeeper",   14,
  2, "Gabriela",    "Observer",   NA,
  3,  "Derrick",    "Observer",   NA,
  3,     "Kara", "Scorekeeper",    9,
  3,    "Emily",    "Observer",   NA,
  3, "Danielle",    "Observer",   NA
)

# The values are inconsistently missing by position within the group
# Use .direction = "downup" to fill missing values in both directions
squirrels %>%
  dplyr::group_by(group) %>%
  fill(n_squirrels, .direction = "downup") %>%
  dplyr::ungroup()
#> # A tibble: 12 × 4
#>    group name     role        n_squirrels
#>    <dbl> <chr>    <chr>             <dbl>
#>  1     1 Sam      Observer              8
#>  2     1 Mara     Scorekeeper           8
#>  3     1 Jesse    Observer              8
#>  4     1 Tom      Observer              8
#>  5     2 Mike     Observer             14
#>  6     2 Rachael  Observer             14
#>  7     2 Sydekea  Scorekeeper          14
#>  8     2 Gabriela Observer             14
#>  9     3 Derrick  Observer              9
#> 10     3 Kara     Scorekeeper           9
#> 11     3 Emily    Observer              9
#> 12     3 Danielle Observer              9

# Using `.direction = "updown"` accomplishes the same goal in this example

源代碼：R/fill.R

相關用法

注：本文由純淨天空篩選整理自Hadley Wickham等大神的英文原創作品 Fill in missing values with previous or next value。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。