计算行含义并将其保存在R(数据表)中的新列中

Question

我有以下数据表：

library(dplyr)
set.seed(123)
dt <- data.table(date = seq(as.Date('2020-01-01'), by = '1 day', length.out = 365),
Germany = rnorm(365, 2, 1), check.names = FALSE)
dt <- dt %>%
mutate(month = format(date, '%b'), 
date = format(date, '%d')) %>%
tidyr::pivot_wider(names_from = date, values_from = Germany) 

我想添加两个新列(monthlyAverage，quarterlyAverage(，一列包含月度平均值，另一列包含季度平均值。

Answer 1

对于月平均值，可以采用逐行平均值，对于四分之一平均值，您可以创建3行的组，并每3个月取一次平均值。

library(dplyr)
dt %>%
mutate(monthlyaverage = rowMeans(.[-1], na.rm = TRUE)) %>%
group_by(grp = ceiling(row_number()/3)) %>%
mutate(quaterlyaverage = mean(monthlyaverage)) %>%
select(month, grp, monthlyaverage, quaterlyaverage, everything()) 

---

如果要使用data.table:

library(data.table)
setDT(dt)[, monthlyaverage := rowMeans(.SD, na.rm = TRUE), .SDcols = -1]
dt[, quaterlyaverage := mean(monthlyaverage), ceiling(seq_len(nrow(dt))/3)]