CODEWITHSUNDEEP
r
azCats
azCats

Reputation: 153

How to sum a column based on specific year?

Suppose I have following time-series data frame in R.

Date           Var1
1/1/2010        7
1/2/2010        154
1/3/2010        125
1/4/2010        87
1/5/2010        57
1/6/2010        12
....
....
7/24/2015       5

If I want Sum(Var1) on year 2010 only, how to do it in R?

Upvotes: 2

Views: 1929

Answers (1)

akrun
akrun

Reputation: 887078

We can use substr to get the 'year' part from 'Date' column, use that in subset to extract the rows that have '2010' as year, select the 'Var1' column, and get the sum

 sum(subset(df1, substr(Date,5,8)==2010, select=Var1))

Or a dplyr/lubridate option would be using filter and summarise to get similar result.

 library(lubridate)
 library(dplyr)
 df1 %>% 
     filter(Date=year(mdy(Date))==2010) %>%
     summarise(Var1= sum(Var1))

Upvotes: 3

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