How do I maximize a vector

Question

I'd like to maximize numbers in a vector and get the results as a new vector

Like this:

w <- 0:10
maximizer <- function(w){
  max(10, w + 5)
}

I'm expecting getting a vector (10,10,10,10,10,10,11,12,13,14,15), but all I'm getting is 15. I know weird ways of fixing this, but I'm sure there must be an easier way...

score 4 · Accepted Answer · answered Feb 10 '19 at 17:21

Instead of max you should use pmax:

maximizer <- function(w) pmax(10, w + 5)
maximizer(0:10)
# [1] 10 10 10 10 10 10 11 12 13 14 15

since

pmax() and pmin() take one or more vectors as arguments, recycle them to common length and return a single vector giving the ‘parallel’ maxima (or minima) of the argument vectors.

while

max and min return the maximum or minimum of all the values present in their arguments

score 0 · Answer 2 · answered Feb 10 '19 at 17:33

0

you could use a for-loop with an ifelse statement albeit not as elegant as the solution posted:

for(i in seq_along(w)){
  w[[i]] <- ifelse(w[[i]]+5 < 10, 10, w[[i]] + 5)
}


[1] 10 10 10 10 10 10 11 12 13 14 15

answered Feb 10 '19 at 17:33

nycrefugee

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`ifelse()` is vectorized, so it could be just `ifelse(w + 5 <= 10, 10, w + 5)` – Rich Scriven Feb 10 '19 at 17:52
@Rich Scriven - for me that kicks an error `Error in w[[i]] <- ifelse(w + 5 < 10, 10, w + 5) : more elements supplied than there are to replace` – nycrefugee Feb 10 '19 at 17:55
With the `for` loop, you may as well just use `if` and `else`: `w[[i]] <- if(w[[i]]+5 < 10) 10 else w[[i]] + 5` – lmo Feb 10 '19 at 18:04
Imo- curious to know if there’s an advantage to using your approach? – nycrefugee Feb 10 '19 at 18:15

How do I maximize a vector

2 Answers2