[英]Row-wise coalesce over all columns
我們如何在不指定列名的情況下對所有列使用dplyr ( tidyverse ) 按行獲取第一個非缺失值 -合並?
示例數據:
df <- data.frame(x = c(NA, "s3", NA, NA,"s4"),
y = c("s1", NA, "s6", "s7", "s4"),
z = c("s1", NA, NA, "s7", NA))
我們可以使用do.call ,但這看起來不太整潔:
df$xyz <- do.call(coalesce, df)
# x y z xyz
# 1 <NA> s1 s1 s1
# 2 s3 <NA> <NA> s3
# 3 <NA> s6 <NA> s6
# 4 <NA> s7 s7 s7
# 5 s4 s4 <NA> s4
這有效,但我不想指定列:
df %>%
mutate(xyz = coalesce(x, y, z))
# x y z xyz
# 1 <NA> s1 s1 s1
# 2 s3 <NA> <NA> s3
# 3 <NA> s6 <NA> s6
# 4 <NA> s7 s7 s7
# 5 s4 s4 <NA> s4
類似於data.table :
library(data.table)
setDT(df)[, xyz := fcoalesce(.SD) ][]
# x y z xyz
# 1: <NA> s1 s1 s1
# 2: s3 <NA> <NA> s3
# 3: <NA> s6 <NA> s6
# 4: <NA> s7 s7 s7
# 5: s4 s4 <NA> s4
失敗的嘗試:
df %>%
mutate(xyz = coalesce(all_vars()))
df %>%
mutate(xyz = coalesce(c_across(all_vars())))
df %>%
rowwise() %>%
mutate(xyz = coalesce(all_vars()))
df %>%
rowwise() %>%
mutate(xyz = coalesce(c_across(all_vars())))
有任何想法嗎?
取自這個GitHub 討論,你可以創建一個coacross
function:
coacross <- function(...) {
coalesce(!!!across(...))
}
df %>%
mutate(xyz = coacross(everything()))
x y z xyz
1 <NA> s1 s1 s1
2 s3 <NA> <NA> s3
3 <NA> s6 <NA> s6
4 <NA> s7 s7 s7
5 s4 s4 <NA> s4
我們可以使用拼接運算符注入數據框進行coalesce
!!!
.
library(dplyr)
df %>% mutate(xyz = coalesce(!!!df))
或者更像“tidyverse”:
df %>% mutate(xyz = coalesce(!!!select(., everything())))
x y z xyz
1 <NA> s1 s1 s1
2 s3 <NA> <NA> s3
3 <NA> s6 <NA> s6
4 <NA> s7 s7 s7
5 s4 s4 <NA> s4
這是可能的解決方案:
df %>%
mutate(xyz = do.call(coalesce,across()))
#> x y z xyz
#> 1 <NA> s1 s1 s1
#> 2 s3 <NA> <NA> s3
#> 3 <NA> s6 <NA> s6
#> 4 <NA> s7 s7 s7
#> 5 s4 s4 <NA> s4
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