如何在两列中查找具有相同值的行？

Question

这有点难以解释，但我正在尝试比较两个不同数据框中的“cpf”列。我想确定来自 (df1) 和 (df2) 的两个“cpf”列中的值何时相等（这些值可以在不同的行中）。之后，如果这些值可从其他数据框中获得，我想更新 NA 值

df1 
    cpf x  y
1   21  NA NA
2   32  NA NA
3   43  NA NA
4   54  NA NA
5   65  NA NA

df2 
    cpf x  y
1   54  5  10
2   0   NA NA
3   65  3   2
4   0   NA NA
5   0  NA NA

我想要以下结果

df3 
    cpf x  y
1   21  NA NA
2   32  NA NA
3   43  NA NA
4   54  5  10
5   65  3   2

Answer 1

我们可以join在“cpf”上做一个并使用fcoalecse

library(data.table)
setDT(df1)[df2, c('x', 'y') := .(fcoalesce(x, i.x), 
        fcoalesce(y, i.y)), on = .(cpf)]

-输出

df1
#   cpf  x  y
#1:  21 NA NA
#2:  32 NA NA
#3:  43 NA NA
#4:  54  5 10
#5:  65  3  2

或者使用coalecsefromdplyr之后left_join

library(dplyr)
left_join(df1, df2, by = 'cpf') %>%
     transmute(cpf, x = coalesce(x.x, x.y), y = coalesce(y.x, y.y))
#  cpf  x  y
#1  21 NA NA
#2  32 NA NA
#3  43 NA NA
#4  54  5 10
#5  65  3  2

在base R，可以使用match

i1 <- match(df1$cpf, df2$cpf, nomatch = 0)
i2 <- match(df2$cpf, df1$cpf, nomatch = 0)
df1[i2, -1] <- df2[i1, -1]

数据

df1 <- structure(list(cpf = c(21L, 32L, 43L, 54L, 65L), x = c(NA_integer_, 
NA_integer_, NA_integer_, NA_integer_, NA_integer_), y = c(NA_integer_, 
NA_integer_, NA_integer_, NA_integer_, NA_integer_)), row.names = c("1", 
"2", "3", "4", "5"), class = "data.frame")

df2 <- structure(list(cpf = c(54L, 0L, 65L, 0L, 0L), x = c(5L, NA, 3L, 
NA, NA), y = c(10L, NA, 2L, NA, NA)), class = "data.frame", row.names = c("1", 
"2", "3", "4", "5"))

Answer 2

df1 %>% 
  left_join(df2, by = "cpf") %>% 
  select(cpf, x = x.y, y = y.y)

输出：

  cpf  x  y
1  21 NA NA
2  32 NA NA
3  43 NA NA
4  54  5 10
5  65  3  2