CODEWITHSUNDEEP
rdate
jakes
jakes

Reputation: 2085

Creating months and years vectors based on two dates

I've got starting date and ending date, like below:

date1 <- '01-03-2011'
date2 <- '30-09-2013'

Based on this I would like two create a vector containing following months and years, something like below:

months <- c(3:12, 1:12, 1:9)
years <- c(rep(2011, 10), rep(2012, 12), rep(2013, 9))

What's the fastest way to do this?

Upvotes: 0

Views: 2602

Answers (3)

G. Grothendieck
G. Grothendieck

Reputation: 269664

Create a yearmon vector by month and then pick off the years and months:

library(zoo)

fmt <- "%d-%m-%Y"
ym <- seq(as.yearmon(date1, fmt), as.yearmon(date2, fmt), by = 1/12)
years <- as.integer(ym)
months <- cycle(ym)

In terms of magrittr pipes:

library(magrittr)
library(zoo)

fmt <- "%d-%m-%Y"
data.frame(date1, date2) %$%
  seq(as.yearmon(date1, fmt), as.yearmon(date2, fmt), by = 1/12) %>% 
  { data.frame(year = as.integer(.), month = cycle(.)) }

Upvotes: 0

acylam
acylam

Reputation: 18681

With lubridate:

library(lubridate)

dates <- seq(dmy(date1), dmy(date2), by = 'month')
months <- month(dates)
years <- year(dates)

or with format in Base R:

months <- as.numeric(format(dates, "%m"))
years <- as.numeric(format(dates, "%Y"))

Output:

> months
 [1]  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5
[28]  6  7  8  9
> years
 [1] 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 2012 2012 2012 2012 2012 2012
[17] 2012 2012 2012 2012 2012 2012 2013 2013 2013 2013 2013 2013 2013 2013 2013

Upvotes: 0

nghauran
nghauran

Reputation: 6768

Try: 

date1 <- "01-03-2011"
date2 <- "30-09-2013"
dates <- seq(as.Date(date1, "%d-%m-%Y"), as.Date(date2, "%d-%m-%Y"), by = "month")
as.numeric(substring(dates, 6, 7)) # months
# [1]  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5  6  7  8  9
as.numeric(substring(dates, 1, 4)) # years
# [1] 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2013
#[24] 2013 2013 2013 2013 2013 2013 2013 2013

Upvotes: 4

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