[R] R is GNU S, not C.... [was "how to get or store ....."]

Wed Dec 7 02:03:41 CET 2005

I think "<-" is better than "=" in some cases.

======= 2005-12-07 08:51:30 Write£º=======

>
>
>======= 2005-12-07 04:17:03 ÄúÔÚÀ´ÐÅÖÐÐ´µÀ£º=======
>
>>From: vincent at 7d4.com
>>> 
>>> ronggui a écrit :
>>> 
>>> > I think it is NOT just for historical reason.
>>> > see the following example:
>>> > 
>>> >>rm(x)
>>> >>mean(x=1:10)
>>> > [1] 5.5
>>> >>x
>>> > Error: object "x" not found
>>> 
>>> x is an argument local to mean(),
>>> did you expect another answer ?
>>> 
>>> >>mean(x<-1:10)
>>> > [1] 5.5
>>> >>x
>>> >  [1]  1  2  3  4  5  6  7  8  9 10
>>> 
>>> What is the goal of this "example" ?
>>
>>I believe it's to show why "<-" is to be preferred over "=" for
>>assignment...
>
>Yeah,I want to show "<-" is to be preferred.
>Sorry for not making it clearly.
>
>>> Here with "<-",
>>> (voluntary, or not, side effect)
>>> the global variable x is, also, created.
>>> Did the writer really want that ???
>>
>>Very much so, I believe.
>> 
>>> I though there were other specific statements
>>> especially intended for global assignment, eg "<<-".
>>
>>You need to distinguish assignment in function _call_ and assignment in
>>function _definition_.  They ain't the same.
>> 
>>> If this example was intended to prove "<-"
>>> is better than "="
>>> ... I'm not really convinced !
>>
>>In that case, let's try another one (which is one big reason I stopped using
>>"=" for assignment):
>>
>>
>>> long.comp <- function(n) {
>>+     Sys.sleep(n)
>>+     n
>>+ }
>>> result = long.comp(30)
>>> system.time(result = long.comp(30))
>>Error in system.time(result = long.comp(30)) : 
>>	unused argument(s) (result ...)
>>> system.time(result <- long.comp(30))
>>[1]  0.00  0.00 30.05    NA    NA
>>> str(result)
>> num 30
>>
>>Cheers,
>>Andy
>> 
>>>
>>
>>______________________________________________
>>R-help at stat.math.ethz.ch mailing list
>>https://stat.ethz.ch/mailman/listinfo/r-help
>>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>
>= = = = = = = = = = = = = = = = = = = =
>			
>
>
> 
>
>2005-12-07
>
>------
>Deparment of Sociology
>Fudan University
>
>My new mail addres is ronggui.huang at gmail.com
>Blog:http://sociology.yculblog.com
>
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

= = = = = = = = = = = = = = = = = = = =

¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡GuangXing
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡guangxing at ict.ac.cn
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡2005-12-07