[英]R Studio - group by dataframe and get statistics using dplyr
我有一个 dataframe:
我想按“ID”和“方向”分组,然后获取“值”的统计信息。 对我来说最难的是对于“类别”列,我需要始终 output 是“ID”组中的最后一个“类别”,如图所示。
我有代码,但结果不可取。 谁能帮我修改现有代码? 感谢您的时间!
ID <- c(1,1,1,2,2,2,3,3)
category <- c("green", "green", "red", "red","green", "green", "yellow", "yellow")
direction <- c("in", "out","in", "out","in", "out","in", "out")
value <- c(4,5,6,7,8,9,10,11)
df <- data.frame(ID, category, direction, value)
res <- df %>%
group_by(ID,direction) %>%
arrange(ID, direction)%>%
summarize(
category = last(category),
sum_value = sum(value),
count_value = length(value)
)
您快到了。 只是您的“最后(类别)”分组仅基于 ID 而不是 ID 和方向。 如果您将其更改为:
res <- df %>%
group_by(ID) %>%
mutate(category = last(category)) %>%
ungroup %>%
group_by(ID, direction, category) %>%
summarise(
sum_value = sum(value),
count_value = length(value)
) %>%
ungroup
它应该可以解决问题。
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