从NA替换为随机值

Question

我想从NA替换为随机值。这个数据框架有一个类似于“每周一天”的列，我不知道如何完成这个数据框架。我试着使用函数miss林，但是这个函数可以工作在带有整数的列上。你知道我怎样才能完成所有的专栏吗？

travel <- read.csv("https://openmv.net/file/travel-times.csv")

library(missForest)
summary(travel)

set.seed(82)
travel1 <- prodNA(travel, noNA = 0.2)
travel2 <- missForest(travel1)

Answer 1

首先，如果要将""字符串读入NAs，则需要在read.csv中添加一个参数na.strings = ""。那么，你的意思是把安娜对一个变量的观察用同一变量的另一个随机观察来代替吗？如果是这样，请考虑以下程序：

travel <- read.csv("https://openmv.net/file/travel-times.csv", na.strings = "")

set.seed(82)
res <- data.frame(lapply(travel, function(x) {
  is_na <- is.na(x)
  replace(x, is_na, sample(x[!is_na], sum(is_na), replace = TRUE))
}))

res看起来像这样

         Date StartTime DayOfWeek GoingTo Distance MaxSpeed AvgSpeed AvgMovingSpeed FuelEconomy TotalTime MovingTime Take407All                                      Comments
1    1/6/2012     16:37    Friday    Home    51.29    127.4     78.3           84.8         8.5      39.3       36.3         No                         Medium amount of rain
2    1/6/2012     08:20    Friday     GSK    51.63    130.3     81.8           88.9         8.5      37.9       34.9         No                             Put snow tires on
3    1/4/2012     16:17 Wednesday    Home    51.27    127.4     82.0           85.8         8.5      37.5       35.9         No                                    Heavy rain
4    1/4/2012     07:53 Wednesday     GSK    49.17    132.3     74.2           82.9        8.31      39.8       35.6         No                     Accident blocked 407 exit
5    1/3/2012     18:57   Tuesday    Home    51.15    136.2     83.4           88.1        9.08      36.8       34.8         No                              Rain, rain, rain
6    1/3/2012     07:57   Tuesday     GSK    51.80    135.8     84.5           88.8        8.37      36.8       35.0         No                           Backed up at Bronte
7    1/2/2012     17:31    Monday    Home    51.37    123.2     82.9           87.3           -      37.2       35.3         No Pumped tires up: check fuel economy improved?
8    1/2/2012     07:34    Monday     GSK    49.01    128.3     77.5           85.9           -      37.9       34.3         No Pumped tires up: check fuel economy improved?
9  12/23/2011     08:01    Friday     GSK    52.91    130.3     80.9           88.3        8.89      39.3       36.0         No                        Police slowdown on 403
10 12/22/2011     17:19  Thursday    Home    51.17    122.3     70.6           78.1        8.89      43.5       39.3         No                    Start early to run a batch

Answer 2

您可以使用imputeTS包向时间序列插入随机值。函数na_random可用于此操作。该函数可用于数值列(其他列将保持不变，这可能很有用，因为您可能不需要注释列的随机文本)

你可以打电话给

library("imputeTS")
na_random(yourData)

该函数将查找每一列的最低值和最高值，并在此界限之间插入随机值。

但是，您也可以为随机值定义自己的边界，如下所示：

library("imputeTS")
na_random(yourData, lower_bound = 0, upper_bound = 25)

对于您的数据，它可能如下所示：

library("imputeTS")

# To read the input correctly and have the right data types
travel <- read.csv("https://openmv.net/file/travel-times.csv", na.strings = "")
travel$FuelEconomy <- as.numeric(travel$FuelEconomy)


# To perform the missing data replacement
travel <- na_random(travel)