Problem with retrieving updated variables after attach()
attach provides a copy of rather than aliases to the variables within a
data frame.
d = data.frame(x=0)
attach(d)
x
# 0, from the attached copy of d
x = 1
x
# 1, from the global anvironment
d$x
# 0, from d
x <<- 2
x
# 1, from the global environment
d$x
# 0, from d
get('x', pos=2)
# 2, from the attached copy of d
rm(x)
x
# 2, from the attached copy of d
vQ
David Croll wrote:
Hello, suppose I have a data frame:
mat
id age 1 NA NA 2 NA NA 3 NA NA 4 NA NA 5 NA NA Then I attach the data frame:
attach(mat)
I assign some new values...
id <<- sample(100,5)
age <<- rnorm(5,mean=30)
Then I want to create a new data frame from the variables id and age which still are attached to position 2 of the R environment...
new_mat <- data.frame(ls(pos=2)) # I want to rescue ALL variables that were created by attach(mat)
new_mat
ls.pos...2. 1 age 2 id But this leads to a bogus object... how can I rescue the updated id and age values into new_mat?