Julio Sergio Santana <juliosergio <at> gmail.com> writes:
>
> I have a data frame whose first colum contains the names of the variables
> and whose second colum contains the values to assign to them:
>
> : kkk <- data.frame(vars=c("var1", "var2", "var3"),
> vals=c(10, 20, 30), stringsAsFactors=F)
>
For those interested in the problem this is how I solved the problem:
I want to have something similar to:
#
# var1 <- 10
# var2 <- 20
# var3 <- 30
my first trial was:
mapply(assign, kkk$vars, kkk$vals)
## var1 var2 var3
## 10 20 30
#
This is, however, what I got:
var1
## Error: object 'var1' not found
David Winsemius suggested me something similar to
mapply(assign, kkk$vars, kkk$vals, MoreArgs = list(pos = 1))
# or:
mapply(assign, kkk$vars, kkk$vals, MoreArgs = list(envir = .GlobalEnv))
var1
## [1] 10
This almost works, but what if this construction is used inside a function?
example <- function () {
var1 <- 250
kkk <- data.frame(vars=c("var1", "var2", "var3"),
vals=c(10, 20, 30), stringsAsFactors=F)
mapply(assign, kkk$vars, kkk$vals, MoreArgs = list(pos = 1))
print (var2)
print (var1)
}
example()
## [1] 20
## [1] 250
var1, which was defined inside the function, isn't modified
To fix this, I defined the function as follows:
example <- function () {
var1 <- 250
kkk <- data.frame(vars=c("var1", "var2", "var3"),
vals=c(10, 20, 30), stringsAsFactors=F)
mapply(assign, kkk$vars, kkk$vals,
MoreArgs = list(pos = sys.frame(sys.nframe())))
# sys.nframe() is the number of the frame created inside the function
# and sys.frame() establishes it as the one assign uses to set values
print (var2)
print (var1)
}
example()
## [1] 20
## [1] 10
And the purpose is got
Thanks,
-Sergio.
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