r语言 - 按两个条件创建新列

Question

我想通过diff= value1 -value3创建新的diff列对于value3或的非缺失值，diff= value1 -value2如果只有value3是NA

data<-data.frame(id=c(1,2,3,4,5,6,7,8),
value1=c(10,12,11,15,16,14,14,11),
value2=c(9,5,6,10,8,10,6,8),
value3=c(4,8,7,NA,9,NA,5,NA))

所需输出:

id value1 value2 value3 diff
1    10    9    4    6
2    12    5    8    4
3    11    6    7    4
4    15   10    NA   5
5    16   8     9    7
6    14   10    NA   4
7    14   6     5    9
8    11   8     NA   3

Answer 1

在dplyr中，您可以使用coalesce来获得value3和value2之间的非na值。

library(dplyr)
data %>% mutate(diff = value1 - coalesce(value3, value2))
#  id value1 value2 value3 diff
#1  1     10      9      4    6
#2  2     12      5      8    4
#3  3     11      6      7    4
#4  4     15     10     NA    5
#5  5     16      8      9    7
#6  6     14     10     NA    4
#7  7     14      6      5    9
#8  8     11      8     NA    3

In base R withifelse-

transform(data, diff = value1 - ifelse(is.na(value3), value2, value3))

和data.table有fcoalesce。

library(data.table)
setDT(data)[, diff := value1 - fcoalesce(value3, value2)]

Answer 2

我们可以使用

library(dplyr)
data %>%
mutate(diff = value1 - case_when(is.na(value3) ~ value2, TRUE ~ value3))
id value1 value2 value3 diff
1  1     10      9      4    6
2  2     12      5      8    4
3  3     11      6      7    4
4  4     15     10     NA    5
5  5     16      8      9    7
6  6     14     10     NA    4
7  7     14      6      5    9
8  8     11      8     NA    3