麻烦把年份变成单独的对象

Question

嗨大家我知道我以前见过这样的帖子，但由于某种原因，我试过的建议都没有奏效。基本上我想要做的是从名为“Production.Period.End.Date”的变量中取出日期，格式为dd/mm/yyyy，并将这些日期的每个部分分成不同的对象进行分析。我这样做的原因是采取标记为“Period_kWh_Production”的年平均千瓦产量并追踪该加班的变化。如果有帮助，我粘贴下面的代码。

setwd（ “C：\用户\ fredd \收存箱\ Grad_Life \ Spring_2017 \ AFM \ Final_Paper \”）

KWTProd.df = read.csv("Merge1//Kwht_Production_07-15.csv", header=T) 

##Did this to verify "Production.Period.End.Date" 

names(KWTProd.df) 

## 
names(KWTProd.df) 
[1] "Application.Number"      
[2] "Program.Administrator"     
[3] "Program"         
[4] "Total.Cost"        
[5] "System.Owner.Sector"      
[6] "Host.Customer.Sector"     
[7] "Host.Customer.Physical.Address.City"  
[8] "Host.Customer.Physical.Address.County" 
[9] "Host.Customer.Physical.Address.Zip.Code" 
[10] "PBI.Payment.."       
[11] "Production.Period.End.Date"    
[12] "Period_kWh_Production" <-IT EXISTS ## 
## 

##Did this to plot changes of Period_kWh_Production over time## 

plot(Period_kWh_Production ~ Production.Period.End.Date, data = KWTProd.df) 

##Tried to do this to aggregate data in average## 

aggregate(Period_kWh_Production~Production.Period.End.Date,KWTProd.df,mean) 

##Still too noisy and can't find the mean by year :C## 

as.date(Production.Period.End.Date, data = KWTProd.df) 

##Says "Production.Period.End.Date" Not found BUT IT EXISTS## 

##Tried this to group and summarise by year but it says: Error in  UseMethod("mutate_") : 
no applicable method for 'mutate_' applied to an object of class "function"   ## 

summary <- df %>% 
    mutate(dates = dmy(Production.Period.End.Date), 
     year = year(Production.Period.End.Date)) %>% 
    group_by(year) %>% 
    summarise(mean = mean(x, na.rm = TRUE), 
      sd = sd(x, na.rm = TRUE)) 

##Trying this but have no clue how I am supposed to use this## 

regexpr("<dd>") 

Answer 1

此代码应取决于dplyr和lubridate包。您尚未提供样本数据。所以这没有经过测试。

library(lubridate) 
library(dplyr) 

summary <- df %>% 
    mutate(end_date = dmy(Production.Period.End.Date), 
     production_year = year(end_date)) %>% 
    group_by(production_year) %>% 
    summarise(mean_kwH = mean(Period_kWh_Production, na.rm = TRUE), 
      sd_kwH = sd(Period_kWh_Production, na.rm = TRUE))