What is the equivalent of += (plus equals) in R [duplicate]

Question

Does R have a concept of += (plus equals) or ++ (plus plus) as c++/c#/others do?

Answer 1

No, it doesn't, see: R Language Definition: Operators

Answer 2

Following @GregaKešpret you can make an infix operator:

`%+=%` = function(e1,e2) eval.parent(substitute(e1 <- e1 + e2))
x = 1
x %+=% 2 ; x

Answer 3

R doesn't have a concept of increment operator (as for example ++ in C). However, it is not difficult to implement one yourself, for example:

inc <- function(x)
{
 eval.parent(substitute(x <- x + 1))
}

In that case you would call

x <- 10
inc(x)

However, it introduces function call overhead, so it's slower than typing x <- x + 1 yourself. If I'm not mistaken increment operator was introduced to make job for compiler easier, as it could convert the code to those machine language instructions directly.

Answer 4

R doesn't have these operations because (most) objects in R are immutable. They do not change. Typically, when it looks like you're modifying an object, you're actually modifying a copy.

Answer 5

Increment and decrement by 10.

require(Hmisc)
inc(x) <- 10 

dec(x) <- 10