按月查找速度的平均值（使用 R）

Question

我这里有数据table：

row      V1      velocity

1   2009-04-06  95.9230769230769

2   2009-04-11  95.0985074626866

3   2009-04-17  95.8064935064935

4   2009-04-22  94.6357142857143

5   2009-04-27  95.3626865671642

6   2009-05-03  95.9101265822785

7   2009-05-08  95.826582278481

8   2009-05-14  94.5126582278481

9   2009-05-20  95.8371428571429

10  2009-05-25  94.6981481481481

11  2009-05-30  96.397619047619

12  2009-06-05  94.8132530120482

13  2009-06-10  96.4558139534884

14  2009-06-16  94.9627906976744

15  2009-06-21  95.2666666666667

16  2009-06-26  95.2919540229885

17  2009-07-01  95.4333333333333

18  2009-07-07  95.3375

19  2009-07-12  95.0534246575343

20  2009-07-18  96.0277777777778

21  2009-07-24  95.6885057471264

22  2009-07-29  93.9375

23  2009-08-03  95.2776315789474

24  2009-08-08  94.9089285714286

25  2009-08-13  96.8906976744186

26  2009-08-19  95.4487804878049

27  2009-08-24  97.2444444444444

28  2009-08-30  95.1174418604651

我想编写一个 r 代码来按月计算速度的平均值。（有5月、6月、7月、8月

我能做什么？

Answer 1

这是我的做法

使用 lubridate 创建一个月份变量以在 dplyr 中分组，然后获取均值。

library(lubridate)
library(dplyr)

df %>% group_by(month = month(df$V1)) %>% summarize(mean = mean(velocity))

         month     mean
1            4 95.36530
2            5 95.53038
3            6 95.35810
4            7 95.24634
5            8 95.81465

如果你添加 label=T 你会得到这个：

df %>% group_by(month = month(df$V1,label=T)) %>% summarize(mean = mean(velocity))

  month     mean
1   Apr 95.36530
2   May 95.53038
3   Jun 95.35810
4   Jul 95.24634
5   Aug 95.81465

Answer 2

或者只是：

tapply(df$velocity, months(as.Date(df$V1)), mean)
   April   August     Juli     Juni      Mai 
95.36530 95.81465 95.24634 95.35810 95.53038

按月查找速度的平均值（使用 R）

Finding a mean value of velocity by month (using R)

average

r

date

subset