R: Creating a New Column with Quarterly dates in r

August 29, 2022

I have the following dataframe:

df = obs seriesA seriesB
1        50       50
2        50       50
3        50       50
4        50       50
5        50       50

I would like to create a new column called date that contains quarterly data from a given interval. e.g.:

df = obs seriesA seriesB   date
1        50       50       Q1-2000
2        50       50       Q2-2000
3        50       50       Q3-2000
4        50       50       Q4-2000
5        45       34       Q1-2001

I would like to have an easy enough method that I can extrapolate to longer data frames: e.g. from Q1-2000 to Q1-2019. Also it would have to be in date format to be able to read it as a date.

>Solution :

You can create a sequence using seq, and then use zoo::as.yearqtr to format the string:

library(zoo)
seq(from = as.yearqtr("2000-01-01"), to = as.yearqtr("2019-01-01"), by = 1/4) |>
  format("Q%q-%Y")

#[1] "Q1-2000" "Q2-2000" "Q3-2000" "Q4-2000" "Q1-2001" "Q2-2001" "Q3-2001" "Q4-2001" "Q1-2002"