R-替换数据帧中的NA

Question

I have a data frame with both quantitative and qualitative variables and contain many missing values

x1    x2      x3
NA    Male    3
NA    Female  7
3     NA      5

I also have another data frame

x1    x2       x3
3     Male     NA
4     NA       NA
NA    NA       NA

Basically I want to replace the NAs in the first data frame with values in the second data frame, column by column. My desire data set is

x1     x2        x3
3      Male      3
4     Female     7
3      Male      5

I am thinking about apply but not sure how to do it efficiently

Answer 1

You can easily combine these two dfs into one using coalesce from dplyr package.

library(dplyr)

First df

df <- data.frame(
  x1 = c(NA, NA, 3),
  x2 = c('Male', 'Female', NA),
  x3 = c(3, 7, 5)
)

Second df

df1 <- data.frame(
  x4 = c(3, 4, NA),
  x5 = c(NA, NA, 'Male'),
  x6 = c(NA, NA, NA)
)

Solution:

df3 <- coalesce(df1, df2)
df3

#  x1     x2 x3
#1  3   Male  3
#2  4 Female  7
#3  3   Male  5