Project Euler Q1 :: Multiples of 3 and 5

Explanation. Standard caveat: don’t look here if you are trying to do these yourself.

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000.

This one’s pretty straight forward, really, as one might hope being the first question. R’s built-in subsetting mechanism handles the extraction fairly nicely. I perhaps would have liked a way to do this without first defining x; though I suppose it could just be repeated in the last line.

## check the worked solution
sum(c(3,5,6,9))
## [1] 23
## values < 1000
x <- 1:999

## sum of x % 3 or x % 5
sum(x[x %% 3 == 0 | x %% 5 == 0])
## [1] 233168
### CORRECT

devtools::session_info()

## ─ Session info ──────────────────────────────────────────────────────────
##  setting  value                       
##  version  R version 3.5.2 (2018-12-20)
##  os       Pop!_OS 19.04               
##  system   x86_64, linux-gnu           
##  ui       X11                         
##  language en_AU:en                    
##  collate  en_AU.UTF-8                 
##  ctype    en_AU.UTF-8                 
##  tz       Australia/Adelaide          
##  date     2019-08-13                  
## 
## ─ Packages ──────────────────────────────────────────────────────────────
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##  backports     1.1.4   2019-04-10 [1] CRAN (R 3.5.2)                   
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## 
## [1] /home/jono/R/x86_64-pc-linux-gnu-library/3.5
## [2] /usr/local/lib/R/site-library
## [3] /usr/lib/R/site-library
## [4] /usr/lib/R/library


rstats 

See also