Python-like unpacking of numeric value in R [dupli

2019-03-25 17:21发布

问题:

This question already has an answer here:

  • Assign multiple new variables on LHS in a single line 14 answers
  • Can I assign variables in batch? [duplicate] 2 answers

In Python, one can do this:

>>> a, b, c = (1, 2, 3)
>>> a
1
>>> b
2
>>> c
3

Is there a way to do it in R, as below?

> a, b, c = c(1, 2, 3)

回答1:

You can do this within a list using [<-

e <- list()

e[c('a','b','c')] <- list(1,2,3)

Or within a data.table using :=

library(data.table)
DT <- data.table()
DT[, c('a','b','c') := list(1,2,3)]

With both of these (lists), you could then use list2env to copy to the global (or some other) environment

list2env(e, envir = parent.frame())

a
## 1
b
## 2
c
## 3

But not in general usage creating objects in an environment.



回答2:

maybe it looks stupid, but I would do this :

v <- list(a=0,b=0,c=0)
v[] <- c(1,2,3)
 v
$a
[1] 1

$b
[1] 2

$c
[1] 3