Re: [R] How to make the assignment in a for-loop not affect variables outside the loop?

2009-12-10 Thread John Fox 
Try

n=10
b=1
local(
for(i in 1:n) {
  n=3
  print(n)
  b - b*i
}
)

print(n)
print(b)

or

n=10
b=1
local(
for(i in 1:n) {
  n=3
  print(n)
  assign(b, b*i, env=.GlobalEnv)
}
)

print(n)
print(b)

John

 -Original Message-
 From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org]
On
 Behalf Of Peng Yu
 Sent: December-09-09 11:03 PM
 To: r-h...@stat.math.ethz.ch
 Subject: Re: [R] How to make the assignment in a for-loop not affect
 variables outside the loop?
 
 2009/11/22 Uwe Ligges lig...@statistik.tu-dortmund.de:
  Either use local as in:
 
  n=10
 
  local(for(i in 1:n){
      n=3
      print(n)
  })
 
  print(n)
 
 'local()' makes everything inside it unavailable outside of it. Is
 there a way to make 'n' unavailable outside but still make 'b'
 available outside without using 'function'?
 
 n=10
 b=1
 local(
 for(i in 1:n) {
   n=3
   print(n)
   b=b*i
 }
 )
 
 print(n)
 print(b)
 
 
  or write a function that is evaluated in its own environment:
 
  n=10
 
  MyLoopFoo - function(){
     for(i in 1:n){
         n - 3
         print(n)
     }
  }
 
  MyLoopFoo()
 
  print(n)
 
 
 
 
  Uwe Ligges
 
 
  Peng Yu wrote:
 
  I know that R is a dynamic programming language. But I'm wondering if
  there is a way to make the assignment in a for-loop not affect
  variables outside the loop.
 
  n=10
  for(i in 1:n){
 
  +     n=3
  +     print(n)
  + }
  [1] 3
  [1] 3
  [1] 3
  [1] 3
  [1] 3
  [1] 3
  [1] 3
  [1] 3
  [1] 3
  [1] 3
 
  print(n)
 
  [1] 3
 
  __
  R-help@r-project.org mailing list
  https://stat.ethz.ch/mailman/listinfo/r-help
  PLEASE do read the posting guide
  http://www.R-project.org/posting-guide.html
  and provide commented, minimal, self-contained, reproducible code.
 
 
 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Re: [R] How to make the assignment in a for-loop not affect variables outside the loop?

2009-12-09 Thread Peng Yu 
2009/11/22 Uwe Ligges lig...@statistik.tu-dortmund.de:
 Either use local as in:

 n=10

 local(for(i in 1:n){
     n=3
     print(n)
 })

 print(n)

'local()' makes everything inside it unavailable outside of it. Is
there a way to make 'n' unavailable outside but still make 'b'
available outside without using 'function'?

n=10
b=1
local(
for(i in 1:n) {
  n=3
  print(n)
  b=b*i
}
)

print(n)
print(b)


 or write a function that is evaluated in its own environment:

 n=10

 MyLoopFoo - function(){
    for(i in 1:n){
        n - 3
        print(n)
    }
 }

 MyLoopFoo()

 print(n)




 Uwe Ligges


 Peng Yu wrote:

 I know that R is a dynamic programming language. But I'm wondering if
 there is a way to make the assignment in a for-loop not affect
 variables outside the loop.

 n=10
 for(i in 1:n){

 +     n=3
 +     print(n)
 + }
 [1] 3
 [1] 3
 [1] 3
 [1] 3
 [1] 3
 [1] 3
 [1] 3
 [1] 3
 [1] 3
 [1] 3

 print(n)

 [1] 3

 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide
 http://www.R-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.


__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

[R] How to make the assignment in a for-loop not affect variables outside the loop?

2009-11-22 Thread Peng Yu 
I know that R is a dynamic programming language. But I'm wondering if
there is a way to make the assignment in a for-loop not affect
variables outside the loop.

 n=10
 for(i in 1:n){
+ n=3
+ print(n)
+ }
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3

 print(n)
[1] 3


__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Re: [R] How to make the assignment in a for-loop not affect variables outside the loop?

2009-11-22 Thread Uwe Ligges 

Either use local as in:

n=10

local(for(i in 1:n){
 n=3
 print(n)
})

print(n)


or write a function that is evaluated in its own environment:

n=10

MyLoopFoo - function(){
for(i in 1:n){
n - 3
print(n)
}
}

MyLoopFoo()

print(n)




Uwe Ligges


Peng Yu wrote:

I know that R is a dynamic programming language. But I'm wondering if
there is a way to make the assignment in a for-loop not affect
variables outside the loop.


n=10
for(i in 1:n){

+ n=3
+ print(n)
+ }
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3
[1] 3

print(n)

[1] 3

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.