ddply，按日期排列

Question

dddly是否可以按月排列數據框而不是按字母順序排列？ 下面是數據的樣本：

df <- data.frame(Count=c(674, 1, 165, 5, 6458, 1809, 141, 35611, 34, 9043, 283, 512, 337, 78761, 131),date=c("12-09", "07-23", "06-02", "06-13", "07-27", "10-16", "06-13", "07-10", "05-22", "11-26", "10-21", "04-03", "04-30", "12-02", "06-14"), Factor=rep(c('a','b','c'),5)) 
df$date <- as.Date(df$date,format="%m-%d") 

ddply排列的字母順序

ddply(df,.(format(date,"%b")),summarize,Sum=sum(Count)) 

我應該如何去按照時間順序把事情的數據？

Answer 1

我推薦使用包像lubridate：

library(lubridate) 
ddply(df, .(month = month(date, label = T, abbr = T)), summarize, Sum = sum(Count)) 
# month Sum 
# 1 Apr 849 
# 2 May 34 
# 3 Jun 442 
# 4 Jul 42070 
# 5 Oct 2092 
# 6 Nov 9043 
# 7 Dec 79435