我想计算我的数据框(df)的每月非累积小计。
"date" "id" "change"
2010-01-01 1 NA
2010-01-07 2 3
2010-01-15 2 -1
2010-02-01 1 NA
2010-02-04 2 7
2010-02-22 2 -2
2010-02-26 2 4
2010-03-01 1 NA
2010-03-14 2 -4
2010-04-01 1 NA
新时期从新月的第一天开始。列“id”用作新期间(== 1)开头的分组变量和期间(== 2)内的观察。目标是在一个月内总结所有更改,然后在下一个时段重新启动0。输出应存储在df的附加列中。
这是我的数据框的可重现的示例:
require(dplyr)
require(tidyr)
require(lubridate)
date <- ymd(c("2010-01-01","2010-01-07","2010-01-15","2010-02-01","2010-02-04","2010-02-22","2010-02-26","2010-03-01","2010-03-14","2010-04-01"))
df <- data.frame(date)
df$id <- as.numeric((c(1,2,2,1,2,2,2,1,2,1)))
df$change <- c(NA,3,-1,NA,7,-2,4,NA,-4,NA)
我试图做的:
df <- df %>%
group_by(id) %>%
mutate(total = cumsum(change)) %>%
ungroup() %>%
fill(total, .direction = "down") %>%
filter(id == 1)
这导致了这个输出:
"date" "id" "change" "total"
2010-01-01 1 NA NA
2010-02-01 1 NA 2
2010-03-01 1 NA 11
2010-04-01 1 NA 7
问题在于cumsum函数,它累积了组中的所有前面的值,并且在新的时间段内不会在0处重新启动。
所需的输出如下所示:
"date" "id" "change" "total"
2010-01-01 1 NA NA
2010-02-01 1 NA 2
2010-03-01 1 NA 9
2010-04-01 1 NA -4
“id”== 1的行显示所有前面列的更改总和,其中“id”== 2,每个周期重新开始为0。是否存在针对此类问题的特定命令?任何人都可以提供上述代码的更正替代品吗?
我们可能还需要在分组变量中使用year-month
格式化的'date'来重置每个月
library(dplyr)
df %>%
group_by(id, grp = format(date, "%Y-%m")) %>%
mutate(total = cumsum(change)) %>%
ungroup() %>%
fill(total, .direction = "down") %>%
filter(id == 1) %>%
ungroup %>%
select(-grp)
# A tibble: 4 x 4
# date id change total
# <date> <dbl> <dbl> <dbl>
#1 2010-01-01 1 NA NA
#2 2010-02-01 1 NA 2
#3 2010-03-01 1 NA 9
#4 2010-04-01 1 NA -4