r - 放置在数据框特定值的特定位置

Question

    DF <- data.frame(x1=c(NA,7,7,8,NA), x2=c(1,4,NA,NA,4)) # a data frame with NA
    WhereAreMissingValues <- which(is.na(DF), arr.ind=TRUE) # find the position of the missing values
    Modes <- apply(DF, 2, function(x) {which(tabulate(x) == max(tabulate(x)))}) # find the modes of each column
DF
WhereAreMissingValues
Modes

我想相应地用模式替换 DF 每一列的 NA。请寻求帮助。

Answer 1

Map 在这里提供了一种单行解决方案:

data.frame(Map(function(u,v){u[is.na(u)]=v;u},DF, Modes))

#  x1 x2
#1  7  1
#2  7  4
#3  7  4
#4  8  4
#5  7  4