How should I deal with 'from' must be of length 1 error?

Question

I tried to count days between specific dates. I have 2 columns with all character vectors.

start.date <- c("2015-01-10","2015-01-11","2015-02-24")
end.date <- c("2015-03-10","2015-04-01","2015-06-13")
date10 <- data.frame(cbind(start.date,end.date))
date10$start.date <- as.character(date10$start.date)
date10$end.date <- as.character(date10$end.date)
str(date10)

and the specific dates are from 2015-04-11 to 2015-07-10. so I made all date which is between the specific dates by using seq(). sp.da1<-ymd("2015-04-11") sp.da2<-ymd("2015-07-10") inteval.da<-seq(sp.da1, sp.da2, by = 'day') I wanted to know how many days are between the specific dates. I tried to use seq(start.date,end.date,by = 'day') like above, but I get this error: 'from' must be of length 1

Please Help me!!!

Solution

You are asking how many days of a given time interval is inside a main time interval.

Let's first set up the three varying time intervals. Then we write a function that checks for every day x whether it is inside or outside the main interval. If we sum up the number of days inside the main interval, we'll have what you're searching for:

date10$start.date <- as.Date.character(date10$start.date, format="%Y-%m-%d")
date10$end.date   <- as.Date.character(date10$end.date,   format="%Y-%m-%d")

your_intervals <- Map(seq, from = date10[, 1], to = date10[, 2], by = "days")

your_intervals is a list with three data frames, each containing every day in the interval.

is_in_interval <- function(x, l_bound = sp.da1, u_bound = sp.da2){
  return (x > l_bound) & (x < u_bound)
}

sapply(your_intervals, function(x) sum(is_in_interval(x)))
# [1] 0 0 63

Comments

[A. Stam]

Is your goal to create a sequence of dates for each row in the dataframe? Or do you just want to know the number of days in between the two dates?

[Dougie Hwang]

If I know how to create a sequence of dates for each row in the dataframe, then I can find the number of days. Can I know both of them?? :)

[A. Stam]

Of course, but if you just want to know the number of days in between, there are easier solutions.

[Dougie Hwang]

Ok, then Could I know the easier way??

[clancy]

this was answered here: stackoverflow.com/questions/28122708/…

[Dougie Hwang]

Error in seq.int(0, to0 - from, by) : wrong sign in 'by' argument I got this error. :( what is the problem??

[A. Stam]

That code isn't similar to the answer I posted - for example, why are you using seq.int? I cannot answer this question unless you provide more information.

[Dougie Hwang]

This code is just sample of my data. Actually I have 20 variables and over 3000 rows. they are in shape of data.frame. Like the code two of them are about date. so I tried to adapt your code to my situation. I can't write my all data in here. :(

[Dougie Hwang]

Error in seq.int(0, to0 - from, by) : wrong sign in 'by' argument I got this error.... Can you give me any clue??

[KenHBS]

Could it be that date[, 2] is smaller than date[, 1] in some of your cases? In the data you posted, it all works..