Calculate Number of Days Between Two Dates in R

calculating number of days between 2 columns of dates in data frame

Without your seeing your data (you can use the output of dput(head(survey)) to show us) this is a shot in the dark:

survey <- data.frame(date=c("2012/07/26","2012/07/25"),tx_start=c("2012/01/01","2012/01/01"))

survey$date_diff <- as.Date(as.character(survey$date), format="%Y/%m/%d")-
                  as.Date(as.character(survey$tx_start), format="%Y/%m/%d")
survey
       date   tx_start date_diff
1 2012/07/26 2012/01/01  207 days
2 2012/07/25 2012/01/01  206 days

count the number of days between two dates per year

Here's one approach using tidyverse and lubridate.

First, separate the rows by calendar year, to use to measure the number of days for each year. Each row will include dates to be counted in each calendar year, starting with January 1st and ending with December 31st if overlapping multiple years. Then, it is easy to calculate the number of days in a given year.

The results from this example are slightly different than what I have. Year 2016 is a leap year and has 366 days. If the number of days are not inclusive of either start or end dates, you would get a different answer.

library(tidyverse)
library(lubridate)

df %>%
  mutate(date_int = interval(start, end),
         year = map2(year(start), year(end), seq)) %>%
  unnest(year) %>%
  mutate(year_int = interval(as.Date(paste0(year, '-01-01')), as.Date(paste0(year, '-12-31'))),
         year_sect = intersect(date_int, year_int),
         start_new = as.Date(int_start(year_sect)),
         end_new = as.Date(int_end(year_sect))) %>%
  select(id, start_new, end_new) %>%
  mutate(year = year(start_new),
         days = as.numeric(end_new - start_new)) %>%
  right_join(df) %>%
  pivot_wider(id_cols = c(id, start, end), names_from = year, values_from = days, names_prefix = "year_", values_fill = list(days = 0)) %>%
  mutate(days_number = reduce(select(., starts_with("year_")), `+`))

Output

     id start      end        year_2015 year_2016 days_number
  <dbl> <date>     <date>         <dbl>     <dbl>       <dbl>
1     1 2015-01-01 2016-12-31       364       365         729
2     2 2016-01-01 2016-12-31         0       365         365
3     3 2015-07-01 2016-12-31       183       365         548

How to calculate average number of days between series of dates?

You can take rowwise differences of 'Date' columns and take the average.

library(dplyr)

df %>%
  mutate(across(starts_with('Date'), as.Date, '%m/%d/%y')) %>%
  rowwise() %>%
  mutate(diff = as.numeric(mean(diff(c_across(starts_with('Date'))), na.rm = TRUE)))

#  Variable Date1      Date2      Date3      Date4       diff
#  <chr>    <date>     <date>     <date>     <date>     <dbl>
#1 VarA     2021-09-01 2021-09-02 2021-09-03 2021-09-04     1
#2 VarB     2021-08-01 2021-08-17 2021-09-02 NA            16
#3 VarC     2021-09-25 NA         NA         NA           NaN

data

It is easier to help if you provide data in a reproducible format

df <- structure(list(Variable = c("VarA", "VarB", "VarC"), Date1 = c("09/01/21", 
"08/01/21", "09/25/21"), Date2 = c("09/02/21", "08/17/21", ""
), Date3 = c("09/03/21", "09/02/21", ""), Date4 = c("09/04/21", 
"", "")), class = "data.frame", row.names = c(NA, -3L))

Calculate the number of weekdays between 2 dates in R

Date1 <- as.Date("2011-01-30")
Date2 <- as.Date("2011-02-04")    
sum(!weekdays(seq(Date1, Date2, "days")) %in% c("Saturday", "Sunday"))

EDIT: And Zach said, let there be Vectorize :)

Dates1 <- as.Date("2011-01-30") + rep(0, 10)
Dates2 <- as.Date("2011-02-04") + seq(0, 9)
Nweekdays <- Vectorize(function(a, b) 
  sum(!weekdays(seq(a, b, "days")) %in% c("Saturday", "Sunday")))
Nweekdays(Dates1, Dates2)

How to calculate number of days between two dates in one column in R

y%>%mutate(Between=as.numeric(lead(Date2,default = last(Date2))-Date2))
       Date2 concentration Between
1 2013-01-01           1.5       7
2 2013-01-08           2.5       4
3 2013-01-12           1.5       5
4 2013-01-17           3.5       0

y%>%mutate(Between=as.numeric(c(diff(Date2),0)))
       Date2 concentration Between
1 2013-01-01           1.5       7
2 2013-01-08           2.5       4
3 2013-01-12           1.5       5
4 2013-01-17           3.5       0

in base R:

 transform(y,Between=as.numeric(c(diff(Date2),0)))

How do I calculate the difference between two dates in dplyr (in days)? R

this is a possible solution;

date1 <- as.Date("2021-09-12")

date2 <- as.Date("2021-09-13")

datediff <- date2 - date1

If you just want the difference as a number

as.numeric(datediff)

with dplyr

library(dplyr)
df <- data.frame(date1 = c("2021-09-12","2021-09-13"),
                 date2 = c("2021-09-13","2021-10-14"))

df$date1 <- df$date1 %>%
  as.Date()
df$date2 <- df$date2 %>%
  as.Date()

df$datediff <- as.numeric(df$date2 - df$date1)

Counting the number of days excluding Sundays between two dates and creating a new column in R DataFrame

I realized with an updated data set that there's a problem with the solution above, when Start-Date and End-Date aren't in the same year. I still want to count the days except Sundays starting on the 20.12.2020 until 10.01.2021 for example. The error message showing up in that case is that the sign with the argument "by" is wrong. I just can't manage to get it running . If I turn the dates around, the output makes no sense and the number of days is too high. What do I have to do to get this running over the year-end?