这是一个(非常快)的方式在data.table。
从里奇使用很好的例子数据:
require(data.table)
days <- seq(as.IDate("2005-10-26"), as.IDate("2010-10-26"), by = "1 day")
n_days <- length(days)
readings <- data.table(
day = days,
sum_flux = runif(n_days),
samples = sample(100, n_days, replace = TRUE),
mean = runif(n_days)
)
readings$sum_flux[sample(n_days, floor(n_days/10))] <- NA
readings
day sum_flux samples mean
[1,] 2005-10-26 0.32838686 94 0.09647325
[2,] 2005-10-27 0.14686591 88 0.48728321
[3,] 2005-10-28 0.25800913 51 0.72776002
[4,] 2005-10-29 0.09628937 81 0.80954124
[5,] 2005-10-30 0.70721591 23 0.60165240
[6,] 2005-10-31 0.59555079 2 0.96849533
[7,] 2005-11-01 NA 42 0.37566491
[8,] 2005-11-02 0.01649860 89 0.48866220
[9,] 2005-11-03 0.46802818 49 0.28920807
[10,] 2005-11-04 0.13024856 30 0.29051080
First 10 rows of 1827 printed.
创建每月的平均,各组出现的顺序:
> avg = readings[,mean(sum_flux,na.rm=TRUE),by=list(mnth = month(day))]
> avg
mnth V1
[1,] 10 0.4915999
[2,] 11 0.5107873
[3,] 12 0.4451787
[4,] 1 0.4966040
[5,] 2 0.4972244
[6,] 3 0.4952821
[7,] 4 0.5106539
[8,] 5 0.4717122
[9,] 6 0.5110490
[10,] 7 0.4507383
[11,] 8 0.4680827
[12,] 9 0.5150618
下一页订货avg
一月开始:
avg = avg[order(mnth)]
avg
mnth V1
[1,] 1 0.4966040
[2,] 2 0.4972244
[3,] 3 0.4952821
[4,] 4 0.5106539
[5,] 5 0.4717122
[6,] 6 0.5110490
[7,] 7 0.4507383
[8,] 8 0.4680827
[9,] 9 0.5150618
[10,] 10 0.4915999
[11,] 11 0.5107873
[12,] 12 0.4451787
现通过参考更新(:=
)sum_flux
列,其中sum_flux
是NA
,其值为avg
。
readings[is.na(sum_flux), sum_flux:=avg$V1[month(day)]]
day sum_flux samples mean
[1,] 2005-10-26 0.32838686 94 0.09647325
[2,] 2005-10-27 0.14686591 88 0.48728321
[3,] 2005-10-28 0.25800913 51 0.72776002
[4,] 2005-10-29 0.09628937 81 0.80954124
[5,] 2005-10-30 0.70721591 23 0.60165240
[6,] 2005-10-31 0.59555079 2 0.96849533
[7,] 2005-11-01 0.51078729** 42 0.37566491 # ** updated with the Nov avg
[8,] 2005-11-02 0.01649860 89 0.48866220
[9,] 2005-11-03 0.46802818 49 0.28920807
[10,] 2005-11-04 0.13024856 30 0.29051080
First 10 rows of 1827 printed.
完成。
通过这样做,你会假设没有趋势,也就是说,每年都有与其他人相似的价值观。你确定你相信吗? –
另外,您想要将平均值应用于“sum_flux”还是“mean”的列? –