CODEWITHSUNDEEP
r
user3652621
user3652621

Reputation: 3634

How do add multiple values to each element of a vector

I'm trying to find all Saturday, Sunday, Monday dates around a series of Sundays. I can get what I want by doing this:

alldays <- Sys.Date() + c(1:100)
allSundays <- alldays[weekdays(alldays)=='Sunday']
length(allSundays) ## 7 elements
nearby <- c(-1,0,1)
result <- c(c(allSundays + nearby[1]),c(allSundays + nearby[2]),c(allSundays + nearby[3]))
length(result) ## 21 elements.

But I'm hoping for a more elegant way of doing it (some form of apply or some dark data.table magic?) My apologies if this is a duplicate, but I could not think of good search terms for this (minor) problem.

Upvotes: 1

Views: 112

Answers (1)

Cath
Cath

Reputation: 24074

One way to do what you want is repeating your sunday vector, nearby will be recycle to the right length:

rep(allSundays, e=3) + nearby

all(sort(result)==(rep(allSundays, e=3) + nearby))
#[1] TRUE

Upvotes: 2

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