我的数据集由两列(时间戳和power)组成:
 str(df2)
'data.frame':   720 obs. of  2 variables:
 $ timestamp: POSIXct, format: "2015-08-01 00:00:00" "2015-08-01 01:00:00" " ...
 $ power    : num  124 149 118 167 130 ..此数据集为期一个月。我想要创建两个子集-一个包含周末数据,另一个包含工作日(星期一至星期五)数据。换句话说,一个数据集应该包含与星期六和星期天相对应的数据,另一个数据集应该包含其他日子的数据。这两个子集都应该保留这两个列。我怎样才能在R中做到这一点?
我尝试使用聚合和拆分的概念,但是我不清楚聚合的函数参数(FUN),我应该如何指定dataset的除数。
发布于 2015-10-14 13:47:17
构建在@ShruS示例之上:
df<-data.frame(timestamp=c("2015-08-01 00:00:00","2015-10-13 00:00:00", "2015-10-11 00:00:00", "2015-10-14 00:00:00"))
df$day<-strptime(df[,1], "%Y-%m-%d")
df$weekday<-weekdays(df$day)
df1 = subset(df,df$weekday == "Saturday" | df$weekday == "Sunday")
df2 = subset(df,df$weekday != "Saturday" & df$weekday != "Sunday")
> df
            timestamp        day   weekday
1 2015-08-01 00:00:00 2015-08-01  Saturday
2 2015-10-13 00:00:00 2015-10-13   Tuesday
3 2015-10-11 00:00:00 2015-10-11    Sunday
4 2015-10-14 00:00:00 2015-10-14 Wednesday
> df1
            timestamp        day  weekday
1 2015-08-01 00:00:00 2015-08-01 Saturday
3 2015-10-11 00:00:00 2015-10-11   Sunday
> df2
            timestamp        day   weekday
2 2015-10-13 00:00:00 2015-10-13   Tuesday
4 2015-10-14 00:00:00 2015-10-14 Wednesday发布于 2015-10-13 16:40:50
您可以使用R基函数来完成此操作,首先使用strptime将日期数据从第一列中分离出来,然后使用函数weekdays。示例:
df1<-data.frame(timestamp=c("2015-08-01 00:00:00","2015-10-13 00:00:00"),power=1:2)
df1$day<-strptime(df1[,1], "%Y-%m-%d")
df1$weekday<-weekdays(df1$day)
df1
 timestamp              power   day      weekday
 2015-08-01 00:00:00     1   2015-08-01  Saturday
 2015-10-13 00:00:00     2   2015-10-13  Tuesday发布于 2015-10-14 04:54:34
最初,我尝试使用额外的库来寻找复杂的方法,但最后,我提出了一种使用R的基本方法。
    #adding day column to existing set 
    df2$day <- weekdays(as.POSIXct(df2$timestamp))    
    # creating two data_subsets, i.e., week_data and weekend_data
    week_data<- data.frame(timestamp=factor(), power= numeric(),day= character())
    weekend_data<- data.frame(timestamp=factor(),power=numeric(),day= character())
    #Specifying weekend days in vector, weekend
    weekend <- c("Saturday","Sunday")
    for(i in 1:nrow(df2)){
      if(is.element(df2[i,3], weekend)){
        weekend_data <- rbind(weekend_data, df2[i,])
      } else{
        week_data <- rbind(week_data, df2[i,])
      }
    }创建的数据集,即weekend_data和week_data是我所需的子数据集。
https://stackoverflow.com/questions/33104456
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