CODEWITHSUNDEEP
rassign
hmnoidk
hmnoidk

Reputation: 565

Assign a negative sign to every value in a vector (in R)?

I want this:

V <- c(2, 3, 4, 5, 6)
V <- as.data.frame(V)

To look like this:

[1] -2 -3 -4 -5 -6

Essentially the reverse of the abs() function. Thanks.

Upvotes: 2

Views: 7638

Answers (2)

Rui Barradas
Rui Barradas

Reputation: 76402

If you don't know beforehand whether all values of the vector are positive, then you should do something like the code below.

V <- c(2, 3, 4, 5, 6)
W <- c(-2, -3, -4, -5, -6)
X <- c(2, -3, 4, -5, 6)

all.neg <- function(x) -1*abs(x)

Let's try it.

all.neg(V)
#[1] -2 -3 -4 -5 -6

all.neg(W)
#[1] -2 -3 -4 -5 -6

all.neg(X)
#[1] -2 -3 -4 -5 -6

If you want to apply it to a data.frame, then do it the usual way.

dat <- data.frame(V, W, X)

dat[] <- lapply(dat, all.neg)
dat
#   V  W  X
#1 -2 -2 -2
#2 -3 -3 -3
#3 -4 -4 -4
#4 -5 -5 -5
#5 -6 -6 -6

Upvotes: 4

Hack-R
Hack-R

Reputation: 23214

You could do

 V * -1

or

-V # first mentioned in the comments by @RHertel

or anything like that. With assignment (updating the object) it looks like this:

v <- v * -1 # or -V

You can also use = for assignment but it goes against the style guides.

[1] -2 -3 -4 -5 -6

Upvotes: 2

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