在 R 中按时间间隔对数据集进行分区 [英] Partitioning data set by time intervals in R

问题描述

我有一些按小时观察的数据.我试图按天甚至每周间隔对这些数据进行子集化.我不确定如何在 R 中继续执行此任务.

I have some observed data by hour. I am trying to subset this data by the day or even week intervals. I am not sure how to proceed with this task in R.

数据样本如下.

date                                 obs
2011-10-24 01:00:00                  12
2011-10-24 02:00:00                  4
2011-10-24 19:00:00                  18
2011-10-24 20:00:00                  7
2011-10-24 21:00:00                  4
2011-10-24 22:00:00                  2
2011-10-25 00:00:00                  4
2011-10-25 01:00:00                  2
2011-10-25 02:00:00                  2
2011-10-25 15:00:00                  12
2011-10-25 18:00:00                  2
2011-10-25 19:00:00                  3
2011-10-25 21:00:00                  2
2011-10-25 23:00:00                  9
2011-10-26 00:00:00                  13
2011-10-26 01:00:00                  11

推荐答案

首先我输入了多个空格替换为制表符的数据.

First I entered the data with the multiple spaces replaced with tabs.

dat$date <- as.POSIXct(dat$date, format="%Y-%m-%d %H:%M:%S")
split(dat , as.POSIXlt(dat$date)$yday)
# Notice these are not the same functions
#---------------------
$`296`
                 date obs
1 2011-10-24 01:00:00  12
2 2011-10-24 02:00:00   4
3 2011-10-24 19:00:00  18
4 2011-10-24 20:00:00   7
5 2011-10-24 21:00:00   4
6 2011-10-24 22:00:00   2

$`297`
                  date obs
7  2011-10-25 00:00:00   4
8  2011-10-25 01:00:00   2
9  2011-10-25 02:00:00   2
10 2011-10-25 15:00:00  12
11 2011-10-25 18:00:00   2
12 2011-10-25 19:00:00   3
13 2011-10-25 21:00:00   2
14 2011-10-25 23:00:00   9

$`298`
                  date obs
15 2011-10-26 00:00:00  13
16 2011-10-26 01:00:00  11

POSIXlt 类在数据帧中不能很好地工作，但它可以非常方便地创建基于时间的组.这是一个具有以下索引的列表结构:'yday'、'wday'、'year'、'mon'、'mday'、'hour'、'min'、'sec'和'isdt'.cut.POSIXt 函数在其他自然边界处添加分割；例如

The POSIXlt class does not work well inside dataframes but it can ve very handy for creating time based groups. It's a list structure with these indices: 'yday', 'wday', 'year', 'mon', 'mday', 'hour', 'min', 'sec' and 'isdt'. The cut.POSIXt function adds divisions at other natural boundaries; E.g.

?cut.POSIXt
  split(dat , cut(dat$date, "week") )

如果您想在日期内求和:

If you wanted to sum within date:

tapply(dat$obs, as.POSIXlt(dat$date)$yday, sum)
#-------
296 297 298 
 47  36  24 

这篇关于在 R 中按时间间隔对数据集进行分区的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！