在R中，如何用组的平均值替换NA值？

Question

我有两个数据帧，第一个（dat）有两列group和value。第二数据帧（dat2）具有每个group的平均值。如何用dat中找到的组的平均值替换dat2中的NA值？

library(dplyr)

x <- as.data.frame(seq(from = 1, to = 10, by = 1))
names(x)[1] <- "value"
y <- as.data.frame(c("A","A","A","A","A","B","B","B","B","B"),1)
names(y)[1] <- "group"

dat <- cbind(y,x)

dat[dat == 3] <- NA
dat[dat == 7] <- NA

dat2 <- dat %>%
  group_by(group) %>%
  summarise_at(.vars = names(.)[2],.funs = c(mean="mean"),na.rm=TRUE)

Answer 1

怎么样？

library(dplyr)

x <- as.data.frame(seq(from = 1, to = 10, by = 1))
names(x)[1] <- "value"
y <- as.data.frame(c("A","A","A","A","A","B","B","B","B","B"),1)
names(y)[1] <- "group"

dat <- cbind(y,x)

dat[dat == 3] <- NA
dat[dat == 7] <- NA

dat %>%
  group_by(group) %>%
  mutate(
    value = ifelse(is.na(value), mean(value, na.rm = T), value)
  ) %>%
  ungroup()