[英]Dealing with dates and times in R
I have a data frame with 2 columns, the first containing dates, and the second containing times, in the format: 我有一个包含2列的数据框,第一列包含日期,第二列包含时间,格式如下:
date time
[1,] "2003-10-03" "22:32:00"
[2,] "2003-10-05" "17:43:06"
[3,] "2003-10-10" "18:45:56"
[4,] "2003-11-12" "17:07:16"
[5,] "2003-11-13" "12:48:04"
[6,] "2003-11-13" "18:17:57"
I would like to create some histograms of these data looking at the number of events per year, per months and at a specific hour of the day. 我想创建一些这些数据的直方图,查看每年,每月和每天特定时段的事件数量。
For the year that's easy 这一年很容易
hist(as.Date(df[,1]), "years")
Now, to get the number of events per months (disregarding the year) I used: 现在,为了获得每个月的事件数量(无视年份),我使用了:
months = c("January", "February", "March",
"April", "May", "June", "July",
"August", "September", "October",
"November", "December")
tb <- table(factor(months.Date(dt), levels=months)
barplot(tb)
Questions: 问题:
Thanks 谢谢
I would use xts, especially if you have data other than dates and times in your data.frame. 我会使用xts,特别是如果你的data.frame中有日期和时间以外的数据。
df$count <- 1
x <- xts(df$count,as.POSIXct(paste(df$date,df$time)))
# create aggregates and plot with plot.zoo()
plot.zoo(period.apply(x, endpoints(index(x),"years"), sum), type="h")
plot.zoo(period.apply(x, endpoints(index(x),"quarters"), sum), type="h")
plot.zoo(period.apply(x, endpoints(index(x),"months"), sum), type="h")
plot.zoo(period.apply(x, endpoints(index(x),"weeks"), sum), type="h")
plot.zoo(period.apply(x, endpoints(index(x),"days"), sum), type="h")
plot.zoo(period.apply(x, endpoints(index(x),"hours"), sum), type="h")
如果你不介意标签是“01”而不是“1月”你可以做这样的事情
barplot(table(format(df$date,"%m")))
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