how to select/subset certain dates in my data set in r-CodePudding

I have a data set for 10 years. I want to select or subset the data by fiscal year using date variable. For date variable is a character. For instance, I want to select data for fiscal year 2020 which is from 01-10-2019 to 30-09-2020. How can I do this in R ?

CodePudding user response：

Here is an example using zoo package:

df1 <- structure(list(dateA = structure(c(14974, 18628, 14882, 16800, 
17835, 16832, 16556, 15949, 16801), class = "Date")), row.names = c(NA, 
-9L), class = c("tbl_df", "tbl", "data.frame"))

library(dplyr)
library(zoo)

df1 %>% 
  mutate(fiscal_year = as.integer(as.yearmon(dateA) - 4/12  1))

output:

  dateA      fiscal_year
  <date>           <int>
1 2010-12-31        2011
2 2021-01-01        2021
3 2010-09-30        2011
4 2015-12-31        2016
5 2018-10-31        2019
6 2016-02-01        2016
7 2015-05-01        2016
8 2013-09-01        2014
9 2016-01-01        2016

CodePudding user response：

as said by @r2evans you should post a minimal reprex.

However with the few information you posted maybe this worked example may fit:

date_vect <- c('01-10-2019','30-07-2020','15-07-2019','03-03-2020')
date_vect[substr(date_vect,7,12) == "2020"]

Under the hypothesis that you have a vector of dates in a string format. You may want to pick all the strings with the last four character equal to 2020 (the year you're interested in).

P.S: It's good practice to use the appropriate format when dealing with dates. You can unlock other features such as ordering with R date libraries.